Pulmatrix (PULM) 10-Q 14 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Trading Symbol	PULM
Entity Registrant Name	Pulmatrix, Inc.
Entity Central Index Key	1,574,235
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		14,516,010

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 25,507	$ 451
Prepaid expenses and other current assets	510	380
Total current assets	26,017	831
Property and equipment, net	545	470
Long-term restricted cash	253	250
Intangible assets	7,534
Goodwill	15,942
Other assets	22
Total assets	50,313	1,551
Current liabilities:
Convertible notes payable to stockholders, net of discount		39,703
Accounts payable	314	216
Accrued expenses	1,013	3,544
Total current liabilities	1,327	43,463
Loan payable, net of discount	6,706
Derivative liability	11
Preferred stock warrant liability		1,309
Deferred tax liability	2,959
Total liabilities	11,003	44,772
Redeemable convertible preferred stock, $0.0001 par value - authorized 500,000 shares and 209,297,265 shares at June 30, 2015 and December 31, 2014, respectively
Junior Seed Convertible Preferred Stock, $0.01 par value - 0 shares and 410,000 shares designated; 0 shares and 410,000 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively; (liquidation preference of $0 and $820 at June 30, 2015 and December 31, 2014)		35,573
Stockholders' Equity (Deficit):
Common stock, $0.0001 par value - 100,000,000 shares and 233,500,000 shares authorized at June 30, 2015 and December 31, 2014; 14,646,108 shares and 188,625 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	1
Additional paid-in capital	157,944	23,142
Accumulated deficit	(118,635)	(101,936)
Total stockholders' equity (deficit)	39,310	(78,794)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$ 50,313	1,551
Series B Redeemable Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, $0.0001 par value - authorized 500,000 shares and 209,297,265 shares at June 30, 2015 and December 31, 2014, respectively
Junior Seed Convertible Preferred Stock, $0.01 par value - 0 shares and 410,000 shares designated; 0 shares and 410,000 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively; (liquidation preference of $0 and $820 at June 30, 2015 and December 31, 2014)		20,894
Stockholders' Equity (Deficit):
Total stockholders' equity (deficit)		20,894
Seed Redeemable Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, $0.0001 par value - authorized 500,000 shares and 209,297,265 shares at June 30, 2015 and December 31, 2014, respectively
Junior Seed Convertible Preferred Stock, $0.01 par value - 0 shares and 410,000 shares designated; 0 shares and 410,000 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively; (liquidation preference of $0 and $820 at June 30, 2015 and December 31, 2014)		1,331
Stockholders' Equity (Deficit):
Total stockholders' equity (deficit)		1,331
Series A-4 Redeemable Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, $0.0001 par value - authorized 500,000 shares and 209,297,265 shares at June 30, 2015 and December 31, 2014, respectively
Junior Seed Convertible Preferred Stock, $0.01 par value - 0 shares and 410,000 shares designated; 0 shares and 410,000 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively; (liquidation preference of $0 and $820 at June 30, 2015 and December 31, 2014)		4,000
Stockholders' Equity (Deficit):
Total stockholders' equity (deficit)		4,000
Series B-1 Redeemable Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, $0.0001 par value - authorized 500,000 shares and 209,297,265 shares at June 30, 2015 and December 31, 2014, respectively
Junior Seed Convertible Preferred Stock, $0.01 par value - 0 shares and 410,000 shares designated; 0 shares and 410,000 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively; (liquidation preference of $0 and $820 at June 30, 2015 and December 31, 2014)		9,344
Stockholders' Equity (Deficit):
Total stockholders' equity (deficit)		9,344
Junior Seed Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, $0.0001 par value - authorized 500,000 shares and 209,297,265 shares at June 30, 2015 and December 31, 2014, respectively
Junior Seed Convertible Preferred Stock, $0.01 par value - 0 shares and 410,000 shares designated; 0 shares and 410,000 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively; (liquidation preference of $0 and $820 at June 30, 2015 and December 31, 2014)		4
Stockholders' Equity (Deficit):
Total stockholders' equity (deficit)		$ 4

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Preferred stock, shares authorized		202,604,452
Preferred stock, shares issued		63,413,042
Preferred stock, shares outstanding		63,413,042
Preferred stock, liquidation value		$ 36,389
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	233,500,000
Common stock, shares issued	14,646,108	188,625
Common stock, shares outstanding	14,646,108	188,625
Redeemable Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	500,000	209,297,265
Series B Redeemable Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	0	180,980,200
Preferred stock, shares issued	0	41,788,790
Preferred stock, shares outstanding	0	41,788,790
Preferred stock, liquidation value	$ 0	$ 20,894
Seed Redeemable Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	0	1,219,508
Preferred stock, shares issued	0	1,219,508
Preferred stock, shares outstanding	0	1,219,508
Preferred stock, liquidation value	$ 0	$ 1,331
Series A-4 Redeemable Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	0	1,307,190
Preferred stock, shares issued	0	1,307,190
Preferred stock, shares outstanding	0	1,307,190
Preferred stock, liquidation value	$ 0	$ 4,000
Series B-1 Redeemable Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	0	18,687,554
Preferred stock, shares issued	0	18,687,554
Preferred stock, shares outstanding	0	18,687,554
Preferred stock, liquidation value	$ 0	$ 9,344
Junior Seed Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	0	410,000
Preferred stock, shares issued	0	410,000
Preferred stock, shares outstanding	0	410,000
Preferred stock, liquidation value	$ 0	$ 820

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Revenues	$ 170		$ 275	$ 8
Operating expenses
Research and development	1,610	$ 1,729	2,528	3,491
General and administrative	9,879	722	11,812	1,379
Total operating expenses	11,489	2,451	14,340	4,870
Loss from operations	(11,319)	(2,451)	(14,065)	(4,862)
Interest expense	(327)	(5,613)	(511)	(6,868)
Loss on the conversion of convertible notes	(1,170)		(1,170)
Fair value adjustment of preferred stock warrant liability	582	1,123	1,309	1,275
Fair value adjustment of derivative liability	(2,692)		(2,291)
Other income, net	29		29	1
Net loss	(14,897)	(6,941)	(16,699)	(10,454)
Net Loss Attributable to Common Stockholders	$ (14,897)	$ (6,954)	$ (16,699)	$ (10,481)
Net loss per share attributable to common stockholders, basic and diluted	$ (2.66)	$ (2.21)	$ (3.79)	$ (3.33)
Weighted average shares used to compute basic and diluted net loss per share attributable to common stockholders	5,608,429	3,145,521	4,401,087	3,145,283

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - Jun. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Convertible Notes [Member]	Convertible Notes [Member]Common Stock [Member]	Convertible Notes [Member]Additional Paid-In Capital [Member]	2015 Bridge Notes [Member]	2015 Bridge Notes [Member]Common Stock [Member]	2015 Bridge Notes [Member]Additional Paid-In Capital [Member]	Series B Redeemable Convertible Preferred Stock [Member]	Seed Redeemable Convertible Preferred Stock [Member]	Series A-4 Redeemable Convertible Preferred Stock [Member]	Series B-1 Redeemable Convertible Preferred Stock [Member]	Junior Seed Convertible Preferred Stock [Member]
Beginning balance at Dec. 31, 2014	$ (78,794)		$ 23,142	$ (101,936)							$ 20,894	$ 1,331	$ 4,000	$ 9,344	$ 4
Beginning balance, shares at Dec. 31, 2014		188,625									41,788,790	1,219,508	1,307,190	18,687,554	410,000
Conversion of preferred stock and notes into common stock	35,573		35,573		$ 43,060	$ 1	$ 43,059	$ 8,407		$ 8,407	$ (20,894)	$ (1,331)	$ (4,000)	$ (9,344)	$ (4)
Conversion of preferred stock and notes into common stock, shares		4,155,539				5,104,655			664,559		(41,788,790)	(1,219,508)	(1,307,190)	(18,687,554)	(410,000)
Issuance of common stock and warrants, shares		1,454,553
Issuance of warrant with term loan	198		198
Exercise of common stock options	$ 150		150
Exercise of common stock options, shares	70,988	70,988
Stock issued for consulting services in connection with the Merger	$ 4,248		4,248
Stock issued for consulting services in connection with the Merger, shares		335,844
Exchange of common stock in connection with the Merger	30,422		30,422
Exchange of common stock in connection with the Merger, shares		2,540,910
Vesting of restricted stock units		130,435
Stock-based compensation	2,745		2,745
Net loss	(16,699)			(16,699)
Ending balance at Jun. 30, 2015	39,310	$ 1	157,944	$ (118,635)
Ending balance, shares at Jun. 30, 2015		14,646,108
Issuance of common stock and warrants	$ 10,000		$ 10,000

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net loss	$ (16,699)	$ (10,454)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	122	162
Stock-based compensation	2,745	146
Stock issued for consulting services in connection with the Merger	4,248
Non-cash rent expense	20
Non-cash interest expense	511	6,868
Fair value adjustment on preferred stock warrant liability	(1,309)	(1,275)
Fair value adjustment on derivative liability	2,291
Loss on conversion of convertible notes	1,170
Loss on disposal of property and equipment	8	59
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	18	(93)
Accounts payable	69	(258)
Accrued expenses	727	98
Restricted cash	(3)	(27)
Net cash used in operating activities	(6,082)	(4,774)
Cash flows from investing activities:
Cash acquired from the merger transaction	9,671
Purchases of property and equipment	(50)	(195)
Net cash provided by (used in) investing activities	9,621	(195)
Cash flows from financing activities:
Proceeds from issuance of common stock and warrants	10,000
Proceeds from exercise of stock options	150
Proceeds from issuance of convertible promissory notes	4,457	5,050
Proceeds from issuance of term loan	6,910
Net cash provided by financing activities	21,517	5,050
Net increase in cash	25,056	81
Cash - beginning of period	451	1,425
Cash - end of period	25,507	1,506
Supplemental disclosures of noncash financing and investing activities:
Promissory note issuance proceeds allocated to beneficial conversion feature		(2,256)
Promissory note issuance proceeds allocated to preferred stock warrants		$ (243)
Conversion of convertible notes and accrued interest into common stock	43,060
Fair value of assets and liabilities acquired in the Merger:
Fair value of assets acquired in Merger	23,772
Fair value of liabilities assumed in Merger	(3,022)
Fair value of net assets acquired in the Merger	$ 20,750

Organization

Organization	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization On June 15, 2015 (the “Effective Time”), Pulmatrix Operating Company, Inc., a Delaware corporation and private company previously known as Pulmatrix Inc. (“Pulmatrix Operating”), completed its merger with Ruthigen Merger Corp. (“Merger Sub”), a wholly owned subsidiary of Pulmatrix, Inc., a Delaware corporation previously known as Ruthigen, Inc. (“Ruthigen”), pursuant to the terms of the Agreement and Plan of Merger (the “Merger Agreement”), dated March 13, 2015, by and among Pulmatrix Operating, Merger Sub and Pulmatrix, Inc. (the “Merger”). Prior to the Merger, Ruthigen was a biopharmaceutical company focused on pioneering new hypochlorus acid, or HOCl, based therapies designed to improve patient outcomes and reduce healthcare costs associated with infections related to post-operative invasive procedures. Following the Merger, Pulmatrix, Inc. is a clinical stage biotechnology company focused on the discovery and development of a novel class of inhaled therapeutic products intended to prevent and treat respiratory diseases and infections with significant unmet medical needs. Pulmatrix Operating’s proprietary dry powder delivery platform, the iSPERSE™ (inhaled Small Particles Easily Respirable and Emitted), is engineered to deliver small, dense particles with highly efficient dispersibility and delivery to the airways, which can be used with an array of dry powder inhaler technologies and can be formulated with a variety of drug substances. Pulmatrix is developing a pipeline of iSPERSE-based therapeutic candidates targeted at prevention and treatment of a range of rare or orphan respiratory diseases and infections, including chronic obstructive pulmonary disease, cystic fibrosis and idiopathic pulmonary fibrosis. The term “Company” as used in these notes to the condensed consolidated financial statements refers to Pulmatrix Operating prior to the completion of the Merger and Pulmatrix, Inc. subsequent to the completion of the Merger.

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	2. Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared on a going concern basis in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (including those which are normal and recurring) considered necessary for a fair presentation of the interim financial information have been included. When preparing financial statements in conformity with GAAP, the Company must make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures at the date of the financial statements. Actual results could differ from those estimates. Additionally, operating results for the three and six months ended June 30, 2015 are not necessarily indicative of the results that may be expected for any other interim period or for the fiscal year ending December 31, 2015. For further information, refer to the financial statements and footnotes included in the Company’s annual financial statements for the fiscal year ended December 31, 2014, which are included in the Company’s current report on Form 8-K/A filed with the SEC on August [X], 2015. Merger and Exchange Ratio The Merger has been accounted for as a “reverse merger” under the acquisition method of accounting for business combinations with Pulmatrix Operating treated as the accounting acquirer of Ruthigen. The historical financial statements of Pulmatrix Operating have become the historical financial statements of the Company, or the combined company, and are included in this filing labeled Pulmatrix, Inc. As a result of the Merger, historical common stock, stock options and additional paid-in capital, including share and per share amounts, have been retroactively adjusted to reflect the equity structure of the combined company, including the effect of the Merger exchange ratio and the common stock par value of $0.0001 per share. See Note 4, “Merger,” for additional discussion of the Merger and the exchange ratio. Reverse Stock Split On June 15, 2015, following the Effective Time, the Company effected a 1-for-2.5 reverse stock split (the “Reverse Stock Split”) of its outstanding common stock, par value $0.0001 per share (“Company Common Stock”). The accompanying condensed consolidated financial statements and notes to the condensed consolidated financial statements, including the Merger exchange ratio (Note 4) applied to historical Pulmatrix Operating common stock and stock options unless otherwise noted, give retroactive effect to the Reverse Stock Split for all periods presented. The shares of Company Common Stock retained a par value of $0.0001 per share.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies In the six months ended June 30, 2015, there were no changes to the Company’s significant accounting policies identified in the Company’s most recent annual financial statements for the fiscal year ended December 31, 2014, which are included in the Company’s current report on Form 8-K/A filed with the SEC on August 14, 2015, except as noted below: Goodwill Goodwill represents the difference between the consideration transferred and the fair value of the net assets acquired and liabilities assumed under the acquisition method of accounting for push-down accounting. Goodwill is not amortized but is evaluated for impairment within the Company’s single reporting unit on an annual basis, during the fourth quarter, or more frequently if an event occurs or circumstances change that would more likely than not reduce the fair value of the Company’s reporting unit below its carrying amount. When performing the impairment assessment, the accounting standard for testing goodwill for impairment permits a company to first assess the qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that the goodwill is impaired. If the Company believes, as a result of the qualitative assessment, that it is more likely than not that the fair value of goodwill is impaired, the Company must perform the first step of the goodwill impairment test. The Company has determined that goodwill was not impaired as of June 30, 2015. In-process Research & Development In-process research & development (“IPR&D”) represents the fair value assigned to research and development assets that were not fully developed at the date of acquisition. IPR&D acquired in a business combination or recognized from the application of push-down When performing the impairment assessment, the Company first assesses qualitative factors to determine whether it is necessary to recalculate the fair value of its acquired IPR&D. If the Company believes, as a result of the qualitative assessment, that it is more likely than not that the fair value of acquired IPR&D is less than its carrying amount, it calculates the asset’s fair value. If the carrying value of the Company’s acquired IPR&D exceeds its fair value, then the intangible asset is written down to its fair value. For the six months ended June 30, 2015, the Company determined that there was no impairment of its IPR&D.

Merger

Merger	6 Months Ended
	Jun. 30, 2015
Business Combinations [Abstract]
Merger	4. Merger As described in Note 1, on June 15, 2015, the Company completed the Merger with Pulmatrix Operating. Pursuant to the Merger Agreement, each outstanding share of capital stock of Pulmatrix Operating was exchanged for 0.148187124066461 pre-Reverse Stock Split shares of Company Common Stock (the “Exchange Ratio”). All Pulmatrix Operating stock options granted under the Pulmatrix Operating stock option plans (whether or not then exercisable) that were outstanding prior to the Effective Time converted into options to purchase Company Common Stock at the same ratio as described below. Immediately prior to the Effective Time, the outstanding shares of convertible preferred stock of Pulmatrix Operating converted into an aggregate of 70,105,854 shares (pre-Reverse Stock Split and before giving effect to the Exchange Ratio) of Pulmatrix Operating common stock, which shares were exchanged in the Merger for an aggregate of 4,155,539 shares of Company Common Stock, and convertible debt of Pulmatrix Operating converted into an aggregate of 86,118,402 shares of Pulmatrix Operating common stock (pre-Reverse Stock Split and before giving effect to the Exchange Ratio), which shares were exchanged in the Merger for an aggregate of 5,104,655 shares of Company Common Stock. All outstanding Pulmatrix Operating preferred stock warrants were cancelled immediately prior to the Effective Time. In addition, immediately following the Effective Time the Company issued 664,559 shares of Company Common Stock in exchange for $4,500 aggregate principal amount of notes assumed by the Company in the Merger. All Pulmatrix Operating stock options granted under the Pulmatrix Operating stock option plans (whether or not then exercisable) that were outstanding at the Effective Time converted into options to purchase Company Common Stock. After the Effective Time, all outstanding and unexercised Pulmatrix Operating stock options assumed by the Company may be exercised solely for shares of Company Common Stock. The number of shares of Company Common Stock subject to each Pulmatrix Operating stock option assumed by the Company was determined by multiplying (a) the number of shares of Pulmatrix Operating common stock that were subject to such Pulmatrix Operating stock option, as in effect immediately prior to the Effective Time, by (b) the Exchange Ratio, and rounding the resulting number down to the nearest whole number of shares of Company Common Stock. The per share exercise price for the Company Common Stock issuable upon exercise of each Pulmatrix Operating stock option assumed by the Company was determined by dividing (a) the per share exercise price of Pulmatrix Operating common stock subject to such Pulmatrix Operating stock option, as in effect immediately prior to the Effective Time, by (b) the Exchange Ratio and rounding the resulting exercise price up to the nearest whole cent. As a result of the Merger, the vesting of 67,732 restricted stock units and 24,400 options granted prior to the Merger by Ruthigen under the Ruthigen 2013 Employee, Director and Consultant Equity Incentive Plan was accelerated. The acceleration clause was included as part of the original terms of the equity awards. The Merger has been accounted for as a reverse acquisition under the acquisition method of accounting with Pulmatrix Operating treated as the accounting acquirer and Ruthigen treated as the acquired company for financial reporting purposes. Pulmatrix Operating was determined to be the accounting acquirer based upon the terms of the Merger and other factors, such as relative voting rights and the composition of the combined company’s board of directors and senior management. Accordingly, the Ruthigen tangible and identifiable intangible assets acquired and liabilities assumed were recorded at fair value as of the date of acquisition, with the excess consideration transferred recorded as goodwill. See Note 11, “Stock-Based Compensation,” for additional details regarding the accounting treatment for the equity awards of Pulmatrix Operating and Ruthigen. The acquisition-date fair value of the consideration transferred is as follows: Number of shares of Company Common Stock owned by Ruthigen stockholders (1) 2,404,835 Multiplied by the price per share of Company Common Stock (2) $ 12.65 Total consideration transferred $ 30,421 (1) The stock transferred in the table above is calculated as the sum of a) 1,921,716 shares of Company Common Stock outstanding at the time of the Merger, b) 379,387 shares of Company Common Stock issued immediately following the closing of the Merger in a private placement, c) 36,000 shares of Company Common Stock issued to certain employees, pursuant to the terms of the Merger Agreement and d) 67,732 shares of Company Common Stock issued pursuant to restricted stock units that became fully vested upon completion of the Merger. (2) The shares outstanding are multiplied by the closing trading price of Company Common Stock as of the Merger date. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the date of acquisition: June 15, 2015 Cash and cash equivalents $ 9,671 In-process research and development 7,534 Goodwill 15,942 Property and equipment 156 Prepaid and other current assets 140 Total assets acquired 33,443 Accrued expenses and other current liabilities (63 ) Deferred tax liability (2,959 ) Total liabilities assumed (3,022 ) Total net assets acquired $ 30,421 The purchase price allocation has been prepared on a preliminary basis and is subject to change as additional information becomes available concerning the fair value and tax basis of the assets acquired and the liabilities assumed. Any adjustments to the purchase price allocation will be made as soon as practicable but no later than one year from June 15, 2015, the acquisition date. For acquired working capital accounts such as prepaid expenses and other current assets, property and equipment, accounts payable and certain accrued expenses, the Company determined that no fair value adjustments were required due to the short timeframe until settlement for these assets and liabilities. The acquired IPR&D consisted of RUT58-60, a proprietary formulation of HOC1 and Ruthigen’s lead drug candidate, which was designed to prevent and treat infection in invasive applications. RUT58-60 was developed in collaboration with Ruthigen’s former parent, Oculus Innovative Sciences, Inc. (“Oculus”), under a license agreement. Concurrent with entering into the Merger Agreement, Pulmatrix, Ruthigen and Oculus entered into a side letter agreement that clarified certain rights and obligations of each party following the closing date of the Merger with respect to certain agreements previously executed between Ruthigen and Oculus, including the license agreement. Under the terms of the side letter agreement, the Company’s obligation to develop and commercialize RUT58-60 was waived for one year following the Merger closing date. Also under the terms of the agreement, the Company may sell its rights to develop RUT58-60 if it receives at least $1,000 therefor, and Oculus has a right of first refusal with respect to any offers to purchase RUT58-60, such that Oculus could elect to purchase RUT58-60 for identical terms negotiated with a prospective buyer. In the event that the Company sells its rights to develop RUT58-60 for an amount in excess of $10,000, the Company must pay 10% of the gross consideration received to Oculus. If, at the end of the one year waiver period, the Company has not been successful in finding a buyer for RUT58-60, Oculus will have the right to cancel the license agreement and reclaim all rights to RUT58-60. The fair value of the IPR&D was determined using a discounted cash flow analysis of the expected cash flows to be generated by the IPR&D over its remaining life, net of returns on contributory assets including working capital and real and personal property assets. A discount rate of 26.6% was used in the analysis. The resulting present value of the cash flows was combined with the estimated present value of the amortization tax benefit that a purchaser of the asset could be expected to receive to arrive at the estimated fair value of the IPR&D. The Company believes the assumptions used are consistent and representative of those a market participant would use in estimating the fair value of the IPR&D. The Company will not begin amortizing the IPR&D asset until the research and development is complete and the asset is reclassified to a finite-lived amortizing asset. Goodwill is calculated as the difference between the acquisition-date fair value of the consideration transferred and the fair values of the assets acquired and liabilities assumed. The goodwill is not expected to be deductible for income tax purposes. Goodwill is recorded as an indefinite-lived asset and is not amortized but tested for impairment on an annual basis or when indications of impairment exist. The deferred tax liability of $2,959 relates to the temporary difference associated with the $7,534 value of the IPR&D asset, which is not deductible for tax purposes. The deferred tax liability was recorded based on a 39.28% effective tax rate. The operating results of Ruthigen for the period from June 16, 2015 to June 30, 2015, including an operating loss of $1,265, have been included in the Company’s condensed consolidated financial statements as of and for the three and six months ended June 30, 2015. The Company incurred a total of $6,863 in transaction costs in connection with the Merger, excluding Ruthigen transaction costs, which were included in general and administrative expense within the consolidated statements of operations for the six months ended June 30, 2015. The following supplemental unaudited pro forma information presents the Company’s financial results as if the acquisition of Ruthigen had occurred on January 1, 2014: Six months ended June 30, 2015 2014 Total revenues, net $ 275 $ 8 Net loss (10,890 ) (16,351 ) The above unaudited pro forma information was determined based on the historical GAAP results of the Company and Ruthigen. The unaudited pro forma consolidated results are not necessarily indicative of what the Company’s consolidated results of operations actually would have been if the acquisition was completed on January 1, 2014. The unaudited pro forma consolidated net loss includes pro forma adjustments primarily relating to the following non-recurring items directly attributable to the business combination: (1) Elimination of $9,956 of transaction costs for both the Company and Ruthigen from the six months ended June 30, 2015, and inclusion of these transaction costs in the six months ended June 30, 2014; (2) Elimination of $901 of stock-based compensation expense related to the acceleration of vesting of previously unvested Ruthigen awards in connection with the Merger from the six months ended June 30, 2015; (3) Elimination of $995 of expense related to stay bonuses from the six months ended June 30, 2015; (4) Elimination of $1,309 of other income and $2,291 of other expense related to the change in the fair values of liability-classified warrants and derivative instruments from the six months ended June 30, 2015, respectively, and $1,275 of other income related to the change in the fair value of liability-classified warrants from the six months ended June 30, 2014, as the Company’s outstanding preferred stock warrants and certain derivative instruments were extinguished in connection with the completion of the Merger; (5) Elimination of $1,170 loss on conversion of convertible notes from the six months ended June 30, 2015, and inclusion of this loss in the six months ended June 30, 2014, as the Company’s 2015 Bridge Notes (defined below) were automatically converted to equity upon completion of the Merger; and (6) Elimination of $477 and $6,868 of interest expense related to our convertible notes, including the 2015 Bridge Notes, from the six months ended June 30, 2015 and 2014, respectively, as all of the Company’s outstanding convertible notes were automatically converted to equity in connection with the closing of the Merger.

Goodwill and IPR&D

Goodwill and IPR&D	6 Months Ended
	Jun. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and IPR&D	5. Goodwill and IPR&D The Company recognized $15,942 of goodwill in connection with the Merger as discussed in Note 4. As of June 30, 2015, there were no accumulated impairment losses. Goodwill has been assigned to the Company’s single reporting unit, which is the single operating segment by which the chief decision maker manages the Company. The Company recognized $7,534 of IPR&D in connection with the Merger as discussed in Note 4. The acquired IPR&D consisted of RUT58-60, a proprietary formulation of HOC1 and Ruthigen’s lead drug candidate, which was designed to prevent and treat infection in invasive applications. The IPR&D will be classified as an intangible asset on the condensed consolidated balance sheet and until the project is completed, the assets will be accounted for as indefinite-lived intangible assets. As of June 30, 2015, there was no accumulated impairment losses associated with intangible assets

Significant Agreements

Significant Agreements	6 Months Ended
	Jun. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Significant Agreements	6. Significant Agreements Palladium Advisory Agreement On February 8, 2015, the Company entered into an agreement with Palladium Capital Advisors, LLC (“Palladium”), whereby Palladium agreed to (i) act as the non-exclusive placement agent for the Bridge Loan financing that occurred on February 26, 2015 (Note 7) and (ii) serve as the Company’s non-exclusive advisor in connection with a merger. As consideration for Palladium’s services under the engagement agreement, the Company paid Palladium a commission on the proceeds received from the issuance of the 2015 Bridge Notes (Note 7) of approximately $315, and issued to Palladium 235,844 shares of the Company’s common stock. On June 16, 2015, the Company paid Palladium $1,080 in commissions, based on a percentage of the unencumbered cash acquired in the Merger (Note 4), a percentage of the amount borrowed under the term loan (Note 7) and a percentage of the cash proceeds raised by the Company in connection with the Merger. The Company recognized expense of $4,378 equal to the sum of the cash payments totaling $1,395 and the fair value of the common stock issued to Palladium of $2,983 within general and administrative expenses in the condensed consolidated statements of operations for the six months ended June 30, 2015. Consulting Agreements On June 15, 2015, Ruthigen entered into consulting agreements with a consulting firm and two associated individuals for services relating to business development, strategic relationships and strategic planning. The agreements were contingent upon the completion of the Merger. The term of the agreements commenced upon the closing of the Merger and expire on August 31, 2016. On June 15, 2015, in connection with the closing of the Merger, the Company issued a total of 100,000 shares of unregistered restricted common stock to the three parties as consideration for services to be provided under the agreements as well as services previously provided. The shares are restricted and cannot be sold or transferred until the contract term has ended. Although the stock was issued as compensation for future services, under the terms of the agreements, the issuance of the stock was issued as non-refundable and without recourse. The Company recognized expense equal to the fair value of the common stock issued of $1,265 within general and administrative expenses in the condensed consolidated statements of operations for the three and six months ended June 30, 2015. Material Transfer Agreement On November 5, 2013, the Company entered into the Material Transfer Agreement (the “MTA”) with Mylan N.V. (“Mylan”). The focus of the MTA is to further the development of PUR0200, the Company’s clinical stage bronchodilator therapy candidate. Under the MTA, the Company has agreed to share materials for the research and development of PUR0200 and Mylan has agreed to share the results of such research activities. The agreement will remain in effect for seven years from the effective date of the agreement or until the completion of Mylan research activities. The agreement is cancelable by either party upon 30 days’ written notice. On June 9, 2015, the Company amended the MTA with Mylan. Under the amended terms of the MTA, the MTA terminates on June 30, 2016 or sooner upon 30 days’ written notice by either party. Additionally under the amended agreement the Company is eligible to receive up to $77 in expense reimbursement to cover the costs to manufacture materials that are transferred under the MTA. There were no amounts recognized in the condensed consolidated financial statements in connection with this agreement during the six months ended June 30, 2015. Long-Acting On March 24, 2015, the Company entered into the long-acting Under the terms of the Mylan Agreement, the Company agreed to conduct certain clinical trials related to the Product and is eligible to receive reimbursement of up to $1,500 for third-party out-of-pocket expenses directly related to trial expenses. As consideration for the funding received, the Company agreed to grant to Mylan an option for the exclusive right to develop, manufacture, commercialize and market any resulting products outside the United States for 180 days following the delivery of a clinical studies report, in exchange for a tiered share of gross profit of up to 20% of such pharmaceutical company’s sales. The Company recognized $170 of revenue under the Mylan Agreement during the three and six months ended June 30, 2015.

Debt

Debt	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Debt	7. Debt Convertible Notes, Including 5X Notes As of December 31, 2014, the Company had outstanding unsecured convertible promissory notes payable to certain existing stockholders with aggregate principal values totaling $29,088 (the “Notes”), including promissory notes with aggregate principal values totaling $2,658 for which, upon settlement of the notes, the note holders would receive five times the stated principal value of the notes, five times the shares into which the rest of the notes would be convertible, or five times the value in new equity shares upon an automatic conversion in a qualified financing (the “5X Notes”). The Notes had a stated annual interest rate of 6%, and the outstanding principal balance of all of the Notes, including the effective principal value of the 5X Notes, and accrued interest were payable on demand by at least a majority of the holders of the Notes, at any time following January 15, 2015, the maturity date, as amended in October 2014, or upon an event of default, as defined within the agreement, at the request of Note holders representing at least a majority of the aggregate principal amount then outstanding under all the Notes. The Notes were unsecured and were issued on various dates during the years ended December 31, 2011, 2012, 2013, and 2014. The Notes had an optional conversion feature where in the event that a qualified financing or a liquidation event, as defined in the Notes, did not occur prior to January 15, 2015, a majority of the Note holders could elect to put the Notes back to the Company for their effective principal amounts, including the five times stated principal amount for the 5X Notes, plus accrued but unpaid interest or to convert all, but not less than all, of the unpaid principal amount of the Notes, plus accrued but unpaid interest through the date of such conversion, into shares of the Company’s Series B Preferred Stock at $0.50 per share. No such qualified financing occurred prior to January 15, 2015 and as such, the Note holders were entitled to put the Notes back to the Company or convert all of the unpaid principal plus interest at any time. In connection with entering into the Merger Agreement (Note 4), the Company and the investors agreed that the Notes would cease to accrue interest as of December 31, 2014. The Company determined that the amendment to cease accrual of interest represented a modification to the Notes. The modification did not give rise to any adjustments to the classification or carrying amounts related to the Notes. On March 13, 2015, pursuant to the Merger Agreement, and as a condition to closing the Merger, the Company entered into a Note Conversion and Warrant Termination Agreement with the holders of the outstanding Notes, including the 5X Notes. Under the terms of the Note Conversion and Warrant termination Agreement, on June 15, 2015, immediately prior to the Effective Time, the outstanding Notes, including the 5X Notes, plus accrued and unpaid interest were automatically converted into 86,118,402 shares (pre-Reverse Stock Split and before giving effect to the Exchange Ratio) of Pulmatrix Operating common stock and all of Pulmatrix Operating’s outstanding warrants to purchase shares of preferred stock were cancelled. No gain or loss was recognized on the conversion of the Notes. These 86,118,402 shares (pre-Reverse Stock Split and before giving effect to the Exchange Ratio) of Pulmatrix Operating common stock were exchanged for 5,104,655 shares of Company Common Stock pursuant to the Exchange Ratio in the Merger. Promissory Note On January 21, 2015, Barry Honig provided the Company with a bridge loan of $350 evidenced by a promissory note. On February 19, 2015, the Company repaid Mr. Honig in full for the promissory note. 2015 Bridge Notes In February 2015, the Company issued and sold convertible promissory notes (the “2015 Bridge Notes”), in the aggregate principal amount of $4,500, of which none was issued to existing investors. The 2015 Bridge Notes had a stated interest rate of 5% per annum, which would reset to 15% upon an event of default, as defined in the agreement, and were due and payable on February 26, 2016. Upon the completion of the Merger, subject to certain limitations, the unpaid principal amount of the 2015 Bridge Notes, plus accrued but unpaid interest through the date of such transaction, automatically converted into shares of common stock of the Company equal to the principal and unpaid accrued interest dollar value divided by $6.875. Upon an event of default, including a change of control other than as defined in the Merger Agreement, at any time or if the Merger had not occurred by February 26, 2016, a majority of the holders of the 2015 Bridge Notes could elect to put the notes back to the Company for the unpaid principal amount of the 2015 Bridge Notes, plus unpaid accrued interest, plus an amount equal to 25% of the outstanding principal balance would become due and payable immediately. The provisions requiring the embedded interest rate reset upon an event of default, automatic conversion of the convertible promissory notes upon the Merger and the put option upon an event of default or failure to close the Merger each represent an embedded derivative instrument requiring bifurcation from the notes. The embedded derivatives were bundled and valued as one compound derivative in accordance with the applicable accounting guidance for derivatives and hedging. The fair value of the compound derivative at issuance of $1,547 was recorded as a derivative liability and as a discount to the 2015 Bridge Notes. The derivative liability was remeasured at fair value at each reporting date, with changes in fair value being recorded as other income (expense) in the statements of operations (Note 12). The net debt discounts resulting from the embedded compound derivative and lender fees were being amortized as interest expense from the date of issuance through the maturity date using the effective interest method. The Company recorded a discount on the 2015 Bridge Notes of $1,547. Amortization of the discount totaled $276 and $386 for the three and six months ended June 30, 2015, respectively. On June 15, 2015, at the Effective Time, Pulmatrix Operating’s obligations under the 2015 Bridge Notes were assumed by Company, and immediately after the Effective Time, the 2015 Bridge Notes, including accrued and unpaid interest, were exchanged for an aggregate of 664,559 shares of Company Common Stock. The exchange of the 2015 Bridge Notes for shares of Company Common Stock resulted in the extinguishment of the embedded compound derivative. Following the exchange, the Company’s obligation to repay the 2015 Bridge Notes was satisfied. Immediately prior to the exchange, the Company recorded a loss of $2,692 for the increase in the estimated fair value of the derivatives. The Company recorded a loss upon the conversion of the 2015 Bridge Notes, including the extinguishment of the embedded compound derivative, of $1,170, equal to the difference between the fair value of the shares issued and the sum of the carrying amount of the 2015 Bridge Notes, including accrued and unpaid interest, and the carrying amount of the compound derivatives at the time of the conversion. The Company incurred interest expense of $326 and $459 during the three and six months ended June 30, 2015, respectively. Loan and Security Agreement and Warrant Agreement On June 11, 2015, Pulmatrix Operating entered into a Loan and Security Agreement (“LSA”) with Hercules Technology Growth Capital, Inc. (“Hercules”), for a term loan in a principal amount of $7,000 (“Term Loan”). On June 15, 2015, following the completion of the Merger, the Company signed a joinder agreement with Hercules making it a co-borrower under the LSA. The entire term loan was funded on June 16, 2015. The term loan is secured by substantially all of the Company’s assets, excluding intellectual property. The term loan bears interest at a floating annual rate equal to the greater of (i) 9.50% and (ii) the sum of (a) the prime rate as reported by The Wall Street Journal minus 3.25% plus (b) 8.50%. The Company is required to make interest payments in cash on the first business day of each month, beginning on July 1, 2015. Beginning on August 1, 2016, the Company will be required to make monthly payments on the first business day of each month consisting of principal and interest based upon a 30-month amortization schedule, and any unpaid principal and interest is due on the maturity date of July 1, 2018. Upon repayment of the term loan, the Company is also required to pay an end of term charge to the Lenders equal to $245. The Company may elect to prepay all, but not less than all, of the outstanding principal balance of the term loan, subject to a prepayment fee of 1% - 3%, depending on the date of repayment. Contingent on the occurrence of several events, including that the Company’s closing stock price exceed $11.73 per share for the seven days preceding a payment date, the Company may elect to pay, in whole or in part, any regularly scheduled installment of principal up to an aggregate maximum amount of $1,000 by converting a portion of the principal into shares of the Company’s common stock at a price of $11.73 per share. Hercules may elect to receive payments in the Company Common Stock by requiring the Company to effect a conversion option whereby Hercules can elect to receive a principal installment payment in shares of the Company Common Stock based on a price of $11.73 per share, subject to an aggregate maximum principal amount of $1,000. The Company determined that the Company’s provisions allowing conversion of all or a portion of the LSA contained a beneficial conversion feature (“BCF”). The BCF is contingent upon the occurrence of certain events and as such, the Company will not record the BCF until the contingency is resolved. Through June 30, 2015 the contingency was not resolved. The credit facility includes affirmative and negative covenants. The affirmative covenants include, among others, covenants requiring the Company to maintain its legal existence and governmental approvals deliver certain financial reports and maintain insurance coverage. The negative covenants include, among others, restrictions on transferring collateral, incurring additional indebtedness, engaging in mergers or acquisitions, paying dividends or making other distributions, making investments, creating liens, selling assets, and undergoing a change in control, in each case subject to certain exceptions. In general, the Term Loan prohibits the Company from (i) repurchasing or redeeming any class of capital stock, including common stock or (ii) declaring or paying any cash dividend or making cash distribution on any class of capital stock, including common stock. In connection with the making of the term loan the Company agreed that Hercules shall have the right to purchase up to $1,000 of securities, under terms and conditions equal to those afforded to other investors, in the event that the Company conducts a private placement for $10,000 or more of securities after the closing date. On June 16, 2015, in connection with the LSA, the Company granted to Hercules a warrant to purchase 25,150 shares of the Company’s common stock at an exercise price of $8.35 per share. The warrants are exercisable in whole or in part any time prior to the expiration date of June 16, 2020. In the event the warrants are not fully exercised, upon the expiration date any outstanding warrants will be automatically exercised for shares of Company Common Stock on a net basis. If the fair market value of one share of Company Common Stock is greater than the exercise price of the warrant, in lieu of exercising the warrant for cash, Hercules may elect to convert all or a portion of the warrant into Company Common Stock on a net basis. The LSA includes provisions requiring the embedded interest rate reset upon an event of default and the put option upon an event of default or qualified change of control each represent an embedded derivative instrument requiring bifurcation from the loan. The embedded derivatives were bundled and valued as one compound derivative in accordance with the applicable accounting guidance for derivatives and hedging. The fair value of the compound derivative at issuance of $11 was recorded as a derivative liability and as a discount to the debt. The derivative liability is remeasured at fair value at each reporting date, with changes in fair value being recorded as other income (expense) in the statements of operations (Note 12). The net debt discounts resulting from the embedded compound derivative and lender fees are being amortized as interest expense from the date of issuance through the maturity date using the effective interest method. The Company incurred interest expense of $34 and $34 during the three and six months ended June 30, 2015, respectively of which $27 and $27, respectively, was payable in cash. The carrying amounts of the Company’s Notes, including the 5X conversion liability, and the Term Loan as of June 30, 2015 and December 31, 2014 were as follows: At June 30, 2015 At December 31, 2014 Outstanding principal: Notes, including 5X Notes $ — $ 29,088 Term Loan 7,000 — 5X conversion liability — 10,633 Debt discount (294 ) (18 ) Carrying amount $ 6,706 $ 39,703 Debt discount activity during the six months ended June 30, 2015 was as follows: Notes, including 2015 Bridge Notes Term Loan Total Balance at December 31, 2014 $ 18 $ — $ — $ 18 Discount on debt issued during the period — 1,547 300 1,847 Amortization of debt discount (18 ) (386 ) (6 ) (410 ) Extinguishment upon conversion of debt — (1,161 ) — (1,161 ) Balance at June 30, 2015 $ — $ — $ 294 $ 294 Future principal payments in connection with the Term Loan are as follows: Remainder of 2015 $ — 2016 1,049 2017 2,701 2018 3,250 $ 7,000 The Company recognized interest expense of $820 and $6,784 during the three and six months ended June 30, 2015, respectively, and $156 and $560 during the three and six months ended June 30, 2014, respectively, related to the accretion of the debt discount.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2015
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	8. Accrued Expenses and Other Current Liabilities Accrued expenses consisted of the following: At June 30, 2015 At December 31, 2014 Accrued vacation $ 81 $ 31 Accrued wages and termination 312 60 Accrued interest payable — 3,338 Accrued clinical & consulting 117 16 Accrued legal & patent 315 44 Accrued other expenses 188 55 Total accrued expenses $ 1,013 $ 3,544

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock and Common Stock	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Redeemable Convertible Preferred Stock and Common Stock	9. Redeemable Convertible Preferred Stock and Common Stock Redeemable Convertible Preferred Stock consisted of the following at December 31, 2014: Shares Common Stock Preferred Stock Issued and Liquidation Carrying Series B 180,980,200 41,788,790 $ 20,894 $ 20,894 2,477,032 Seed 1,219,508 1,219,508 1,331 1,331 72,293 Series A-4 1,307,190 1,307,190 4,000 4,000 474,201 Series B-1 18,687,554 18,687,554 9,344 9,344 1,107,706 Junior Seed 410,000 410,000 820 4 24,307 202,604,452 63,413,042 $ 36,389 $ 35,573 4,155,539 On March 13, 2015, pursuant to the Merger Agreement, and as a condition to closing the Merger, the Company entered into a Preferred Stock Conversion Agreement, under the terms of which, immediately prior to the completion of the Merger, each series of the Pulmatrix Operating’s preferred stock would be automatically converted into shares of Pulmatrix Operating’s common stock. On June 15, 2015, prior to the Effective Time, Pulmatrix Operating had 63,413,042 shares of Redeemable Convertible Preferred Stock outstanding, which were convertible into 70,105,854 shares (pre-Reverse Stock Split and before giving effect to the Exchange Ratio) of Pulmatrix Operating common stock. Immediately prior to the completion of the Merger, the outstanding shares of Redeemable Convertible Preferred Stock were converted into 70,105,854 shares (pre-Reverse Stock Split and before giving effect to the Exchange Ratio) of Pulmatrix Operating common stock. Pulmatrix Operating Private Placement On June 15, 2015, immediately prior to the Effective Time, pursuant to a securities purchase agreement between the Company and certain existing investors of the Company dated March 13, 2015, the Company sold to such investors 24,538,999 units, with each unit consisting of (i) one share of Pulmatrix Operating’s common stock and (ii) a warrant representing the right to purchase 2.193140519 shares of Pulmatrix Operating common stock at an exercise price of $0.448266 per share (each pre-Reverse Stock Split and before giving effect to the Exchange Ratio), for aggregate gross proceeds of $10,000 (the “Pulmatrix Operating Private Placement”). Upon the Effective Time, the Pulmatrix Operating common stock underlying the units was exchanged for an aggregate of 1,454,553 shares of Company Common Stock, and the warrants underlying the units were converted into warrants to purchase an aggregate of 3,190,030 shares of Company Common Stock at an exercise price of $7.563 per share. The proceeds from the issuance of the units were allocated between the Company Common Stock and the warrants based on their relative fair values. Ruthigen Private Placement Immediately after the Effective Time, the Company closed a private placement of 379,387 shares of Company Common Stock at a price of $6.875 per share in a private placement for aggregate gross proceeds of approximately $2.6 million (the “Ruthigen Private Placement”).

Warrants

Warrants	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Warrants	10. Warrants Preferred Stock Warrants Issued with Notes Payable to Stockholders Pulmatrix Operating issued warrants to purchase preferred stock in connection with the issuance of Notes to stockholders (Note 7) on various dates in 2011 through 2014 (the “Preferred Stock Warrants”). The number and type of shares issuable upon exercise of the warrants was variable based on the following: (a) upon the completion of a qualified financing, the warrants would be exercisable into a number of qualified financing shares determined by multiplying 0.25 by the quotient obtained by dividing the original principal amount of the Notes by the issuance price in the qualified financing or, (b) upon the completion of an optional conversion of the Notes into shares of Series B Preferred stock by the Note holders, the warrants would be exercisable into a number of shares of Series B Preferred stock determined by multiplying 0.25 by the quotient obtained by dividing the original principal amount of the Notes by $0.50 (subject to any adjustments for any stock splits, combinations, reclassifications, and the like). If the Preferred Stock Warrants had become exercisable into a number of qualified financing shares, the exercise price per share would have been the per share issuance price of the qualified financing shares. If the Preferred Stock Warrants had become exercisable into shares of Series B Preferred stock, the exercise price would have been $0.50 per share. The Preferred Stock Warrants were exercisable at any time on or after the earlier of a qualified financing or an optional conversion of the Notes and expire 10 years from the date of issuance. As described more fully in Note 7, the Company entered into a Note Conversion and Warrant Termination Agreement with the holders of the outstanding Notes, under the terms of which all of the Company’s outstanding Preferred Stock Warrants were terminated on June, 15, 2015, immediately prior to the Effective Time. As of June 30, 2015, there were no outstanding Preferred Stock Warrants. A rollforward of the Preferred Stock Warrants is as follows: Preferred Stock Estimated Fair Balance—December 31, 2014 14,544,247 $ 1,309 Decrease in estimated fair value of warrants — (1,309 ) Cancellation and gain (loss) on extinguishment (14,544,247 ) — Balance—June 30, 2015 — $ — For the three and six months ended June 30, 2015, the Company recorded other income of $152 and $1,032, respectively, and for the three and six months ended June 30, 2014, the Company recorded other income of $727 and $1,309, respectively, in each case related to the change in the fair value of the warrants classified as liabilities. Common Stock Warrants Issued in Pulmatrix Operating Private Placement As described in Note 9, at June 30, 2015, the Company had outstanding warrants to purchase 3,190,030 shares of Company Common Stock at an exercise price of $7.563 per share. The warrants were issued on June 15, 2015 immediately prior to the Effective Time in connection with the Pulmatrix Operating Private Placement. Each warrant issued in the Pulmatrix Operating Private Placement has a five-year term and becomes exercisable at the earliest to occur of the date that (i) the Company enters into a strategic license agreement with a third party related to any of the Company’s products whereby the Company is guaranteed to receive consideration having a value of at least $20,000, (ii) the Company consummates a public or private offering of common stock or securities convertible into common stock that results in aggregate gross proceeds of at least $20,000 and the per share value of such consideration is equal to at least $10.00 per share, subject to certain adjustments, (iii) for a period of sixty consecutive trading days, the volume weighted average price per share of common stock exceeds $12.50, subject to certain adjustments, and the average daily trading volume on such trading market exceeds 40,000 shares per trading day, subject to certain adjustments, or (iv) a change of control transaction occurs. The number of shares of common stock underlying each warrant and the exercise price per share are subject to adjustment in the case of standard dilutive events. Each warrant provides that, following it initially becoming exercisable, if (i) the volume weighted average price of common stock exceeds one hundred fifty percent (150%) of the exercise price of the warrant for thirty (30) consecutive trading days, (ii) the daily trading volume for common stock exceeds 80,000 shares per trading day, subject to certain adjustments, for thirty (30) consecutive trading days and (iii) there is an effective registration statement under the Securities Act of 1933, as amended, covering the resale of the shares of common stock issuable upon the exercise of the warrant, then the Company shall cancel the unexercised portion of the warrant for consideration equal to $0.001 per share of common stock underlying the warrant. The proceeds from the issuance of the units were allocated between the Company Common Stock and the warrants based on their relative fair values. The value allocated to the warrants was classified within equity on Company’s condensed consolidated balance sheet. Warrants Assumed in Merger Between March 2014 and May 2014, in connection with its initial public offering (“IPO”), Ruthigen issued warrants to purchase an aggregate of 1,219,000 units (the “Series A Warrants”). The Series A Warrants were originally each exercisable at a price of $18.125 per warrant for (x) 0.4 shares of common stock and (y) a warrant (the “Series B Warrant”) to purchase 0.4 shares of common stock at an exercise price of $22.65625 per share. The Series A Warrants are exercisable from the date of issuance and terminate on the second anniversary of the date of issuance. The exercise price and the number of shares for which each Series A Warrant may be exercised is subject to adjustment in the event of stock dividends, stock splits, reorganizations or similar events affecting the Company’s common stock. In addition, subject to certain exceptions, the exercise price of each the Series A Warrants and the Series B Warrants is subject to a weighted average reduction if the Company issues shares of common stock (or securities convertible into common stock) in the future at a price below both (a) the current exercise price of the Series A Warrant; and (b) the current market price of the Company’s common stock. The Series A Warrants may be called by the Company, for consideration equal to $0.00025 per Series A Warrant, on not less than 10 business days’ notice if the closing price of the common stock is above 150% of the $18.125 IPO price per unit for any period of 20 consecutive business days ending not more than three business days prior to the call notice date. The Series B Warrants will be exercisable upon issuance and will terminate on the fifth anniversary of the date of issuance. The Company agrees that, during the period the Series A Warrants are outstanding, it will maintain the effectiveness of the registration statement such that the holder may exercise the Series A Warrants to receive registered shares of common stock and registered Series B Warrants (and the shares of common stock underlying the Series B Warrants). The Company determined that the Series A and Series B Warrants are equity instruments because the warrants are (a) freestanding financial instruments; (b) indexed to the Company’s own stock; (c) not permitted to be settled for cash; and (d) exercisable into common stock for which the Company has sufficient authorized and unissued shares. Immediately following the Merger, the Company issued 136,000 shares of its common stock to Ruthigen’s financial advisor and an aggregate of 379,387 shares in the Ruthigen Private Placement at a price of $6.875 per share. Pursuant to the weighted average exercise price reduction provisions of the Series A Warrants and the Series B Warrants, these issuances caused the exercise price per unit of the Series A Warrants and the exercise price per share of the Series B Warrants to drop to $17.83 and $22.28, respectively. Ruthigen issued to the representative of the underwriters in the IPO warrants to purchase 37,100 shares of the Company’s common stock at an exercise price of $22.65625 per share (the “Representative’s Warrants”). The Representative’s Warrants are exercisable commencing on March 21, 2015 and expire on March 21, 2019. Following the closing of the IPO and in connection with the IPO, the underwriters exercised a portion of the over-allotment option. In connection with the underwriters’ partial exercise of the over-allotment option, Ruthigen issued to the representative of the underwriters a five-year warrant to purchase an additional 2,160 shares of the Company’s common stock at an exercise price of $22.65625 per share (“Underwriter’s Warrant”). The Underwriter’s Warrant is exercisable commencing one year from the date of issuance. Common Stock Warrants Issued with Term Loan As described in Note 7, on June 11, 2015, Pulmatrix Operating entered into a LSA with Hercules for a Term Loan in the principal amount of $7,000. On June 16, 2015, in connection with the LSA, the Company granted to Hercules a warrant to purchase 25,150 shares of Company Common Stock (the “Hercules Warrants”) at an exercise price of $8.35 per share. The warrants are exercisable in whole or in part any time prior to the expiration date of June 16, 2020. In the event the warrants are not fully exercised, upon the expiration date any outstanding warrants will be automatically exercised for shares of Company Common Stock on a net basis. If the fair market value of one share of Company Common Stock is greater than the exercise price of the warrant, in lieu of exercising the warrant for cash, Hercules may elect to convert all or a portion of the warrant into Company Common Stock on a net basis. A portion of the proceeds from the Term Loan were allocated to the warrants based on their grant date fair value. The value allocated to the warrants of $198 was classified within equity on Company’s condensed consolidated balance sheet, with a corresponding amount recorded as a discount to the debt. The fair value of the warrants was determined using the Black-Scholes option pricing model, using the following assumptions: Exercise price $ 8.35 Fair value of underlying stock $ 11.80 Expected volatility 72.52 % Contractual term 5 years Risk-free interest rate 1.68 % Expected dividend yield 0 % The following represents a summary of the warrants outstanding at each of the dates identified: Number of Shares Underlying Warrants Warrants Issue Date Classification Exercisable For June 30, 2015 December 31, 2014 Preferred Stock Warrants Various Liability Preferred Stock — 14,544,247 Private Placement Warrants June 15, 2015 Equity Common Stock 3,190,030 — Hercules Warrants June 15, 2015 Equity Common Stock 25,150 — Warrants Assumed in Merger Series A Warrants March - May 2015 Equity Common Stock 1,219,000 — Representative’s Warrants March 2015 Equity Common Stock 37,100 — Underwriter’s Warrant March 2015 Equity Common Stock 2,160 —

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	11. Stock-Based Compensation The Company sponsors the Ruthigen, Inc. Amended and Restated 2013 Employee, Director and Consultant Equity Incentive Plan, and immediately following the Effective Time, renamed the plan the Pulmatrix, Inc. 2013 Employee, Director and Consultant Equity Incentive Plan (the “2013 Plan”). The 2013 Plan was amended and restated at the Effective Time to, among other things, (i) increase the number of shares of Company Common Stock authorized under the plan, (ii) comply with the requirements imposed by Section 162(m) of the Internal Revenue Code of 1986, as amended, and (iii) provide an increase in the number of shares of Company Common Stock available for issuance under the 2013 Plan’s “evergreen” provision. As of June 30, 2015, the 2013 Plan provides for the grant of up to 2,713,261 shares of Company Common Stock, of which 1,191,598 shares remained available for future grant at June 30, 2015. At the Effective Time, the Company assumed Pulmatrix Operating’s 2013 Employee, Director and Consultant Equity Incentive Plan (the “Original 2013 Plan”) and Pulmatrix Operating’s 2003 Employee, Director, and Consultant Stock Plan (the “2003 Plan”). At the Effective Time, the Company terminated the Original 2013 Plan as to future awards. An aggregate of 35,556 and 629,983 shares of Company Common Stock may be delivered under options outstanding as of June 30, 2015 under the Original 2013 Plan and the 2003 Plan, respectively, however no additional awards may be granted under the Original 2013 Plan or the 2003 Plan. In connection with the Merger, all outstanding stock options of Pulmatrix Operating converted into stock options to purchase Company Common Stock, subject to the Exchange Ratio. The conversion of the Pulmatrix Operating stock options for stock options to purchase Company Common Stock was treated as a modification of the awards. The modification of the stock options did not result in any incremental compensation expense as the modification did not increase the fair value of the stock options. Options The following table summarizes stock option activity for the six months ended June 30, 2015: Number of Weighted- Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding—December 31, 2014 732,823 $ 2.08 6.73 $ 5,508 Granted 1,299,251 $ 11.56 Options assumed in Merger 24,400 $ 14.07 Exercised (70,988 ) $ 2.11 Forfeited or expired (2,016 ) $ 2.16 Outstanding—June 30, 2015 1,983,470 $ 8.44 9.07 $ 4,339 Exercisable—June 30, 2015 694,942 $ 3.73 7.71 $ 5,582 Vested or expected to vest—June 30, 2015 1,888,088 $ 8.31 9.03 $ 6,535 The weighted-average grant-date fair values of stock options granted during the six months ended June 30, 2015 was $11.56 per share. During the six months ended June 30, 2015, the Company received cash of $150 from the exercise of options. The intrinsic value of options exercised during the six months ended June 30, 2015 was $531. As of June 30, 2015 there was $8,132 of unrecognized stock-based compensation expense related to unvested stock options granted under the Company’s stock award plans. This expense is expected to be recognized over a weighted-average period of approximately 9.95 years. The following table presents the stock-based compensation expense related to option awards for the three and six months ended June 30: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Research and development $ 50 $ 40 $ 81 $ 105 General and administrative 2,661 15 2,664 41 Total stock based compensation expense $ 2,711 $ 55 $ 2,745 $ 146 The estimated fair values of employee stock options granted during the six months ended June 30, 2015 and 2014, were determined on the date of grant using the Black-Scholes option-pricing model with the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Expected option life (years) 1.48 - 6.12 5.96 1.48 - 6.22 5.96 Risk-free interest rate 0.68% - 1.91% 1.54% 0.68% - 1.91% 1.54% - 1.57% Expected volatility 65.85% - 73.33% 133% 73.33% - 132.0% 131% - 133% Expected dividend yield 0% 0% 0% 0% Restricted Stock Units In connection with the Merger, the Company signed one-year employment agreements with the former CEO and CFO of Ruthigen pursuant to which the Company granted 329,052 RSUs of which 130,435 RSUs were immediately vested upon the date of the grant. The Company recorded stock-based compensation expense of $1,755 for the RSUs vested during the three and six months ended June 30, 2015. The following table summarizes stock RSU activity for the six months ended June 30, 2015: Number of Weighted- Fair Value Total Grant Date Outstanding—December 31, 2014 — $ — $ — Granted 329,052 $ 12.65 4,163 Vested (130,435 ) $ 12.65 (1,650 ) Forfeited or expired — — — Outstanding—June 30, 2015 198,617 $ 12.65 $ 2,513

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	12. Fair Value Measurements Information about the liabilities measured at fair value on a recurring basis as of June 30, 2015 and December 31, 2014, and the input categories associated with those liabilities is as follows: June 30, 2015 Fair Value Measurements Using Level 1 Level 2 Level 3 Total Liabilities: Embedded compound derivative $ — $ — $ 11 $ 11 December 31, 2014 Fair Value Measurements Using Level 1 Level 2 Level 3 Total Liabilities: Preferred stock warrants $ — $ — $ 1,309 $ 1,309 Preferred Stock Warrants The fair values of the preferred stock warrants were determined using the Hybrid Model which consists of the guideline public company (“GPC”) analysis, a market-based approach to estimate the enterprise value of the Company, and the Option Pricing Model (“OPM”) to allocate the enterprise value to each security. The GPC analysis is based upon the premise that indications of value for a given entity can be estimated based upon the observed valuation multiples of comparable public companies, the equity of which is freely-traded by investors in the public securities markets. Under the OPM, shares are valued by creating a series of call options with exercise prices based on the liquidation preferences and conversion terms of each equity class and use inputs such as equity value, time to liquidity, volatility, risk-free rate, dividend yield and strike price. The warrants and underlying convertible redeemable preferred stock were subsequently valued using a back-solve method within the OPM framework to arrive at a concluded fair value of the common stock of the Company. The back-solve method is used when a recent financing has taken place which establishes a reference value for one or more classes of stockholders. The issuance and sale of the Notes, which took place during 2014, was used as the basis for the valuation during the year ended December 31, 2014. The equity value was allocated to the various share classes based upon their respective claims on a series of call options with strike prices at various value levels depending upon the rights and preferences of each class. The exercise price and number of shares underlying the warrants were determined and the value calculated within the allocation model. The allocation factor was applied to the fair value of the warrants to determine their fair value at December 31, 2014. As described more fully in Note 7, on March 13, 2015, the Company entered into a Note Conversion and Warrant Termination Agreement with the holders of the outstanding warrants, under the terms of which all of the Company’s outstanding warrants to purchase shares of preferred stock were terminated on June, 15, 2015, the Effective Time of the Merger. As of June 30, 2015, there were no outstanding warrants to purchase preferred stock. The following table provides quantitative information about the fair value measurements, including the range of assumptions for the significant unobservable inputs used in the hybrid method valuations of the warrant liability and “with and without” method used for the embedded compound derivative: At December 31, 2014 Time to liquidity event 0.50 years Risk-free interest rate 0.12% Volatility 60% Minority discount 10% Discount for lack of marketability 23% Embedded Compound Derivatives – 2015 Bridge Notes The 2015 Bridge Notes contained an embedded interest rate reset upon an event of default, automatic conversion of the convertible promissory notes upon a Merger or combination with Ruthigen and a put option upon an event of default or the failure to execute a Merger or combination with Ruthigen, each of which represented an embedded derivative instrument requiring bifurcation from the 2015 Bridge Notes. The embedded derivatives were bundled and valued as a single compound derivative. The fair value of the derivative upon issuance of $1,547 was recognized as a derivative liability and adjusted to fair value at each reporting date. As described in Note 7, on June 15, 2015, immediately after the Effective Time, the embedded compound derivative was extinguished in connection with the exchange of the 2015 Bridge Notes, including accrued and unpaid interest, into shares of Company Common Stock. Immediately prior to the exchange, the Company remeasured the fair value of the derivatives. Management determined that the derivatives tied to the probability of events of default had no value, as the probability of defaulting on the 2015 Bridge Notes immediately prior to their exchange was zero. At the same time, management determined the probability of exchange of the 2015 Bridge Notes at 100%, thereby resulting in an increase in the fair value of the contingent automatic exchange feature. The Company recorded a loss of $2,692 for the increase in the estimated fair value of the contingent automatic exchange feature immediately prior to the exchange of the 2015 Bridge Notes. The Company recorded a loss upon the exchange of the 2015 Bridge Notes, including the extinguishment of the embedded compound derivative, of $1,170 during the three and six months ended June 30, 2015. Embedded Compound Derivatives – LSA with Hercules As described in Note 7, the LSA contains an interest rate reset upon an event of default and a put option upon an event of default or qualified change of control. Each of these features represents an embedded derivative instrument requiring bifurcation from the Term Loan. The embedded derivatives were bundled and valued as one compound derivative in accordance with the applicable accounting guidance for derivatives and hedging. The proceeds from the issuance of the Term Loan were allocated first to the warrant and compound derivative at their respective fair values, with the residual going to the carrying amount of the loan resulting in a discount to the face value of the debt. The fair value of the compound derivative upon issuance of $11 was recognized as a derivative liability and will be adjusted to fair value at each reporting date. The fair value of the derivative instruments is based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The Company used an income approach to estimate the fair value of the derivative liability and estimated the probability of an event of default occurring at various dates and then estimates the present value of the amount the holders would receive upon an event of default. The significant assumption used in the model is the probability of the following scenarios occurring: At Issuance Date At June 30, 2015 Probability of an event of default 10% * Prepayment penalties 1.0% - 3.0% * End of term payment $245,000 * Risk-free interest rate 1.01% * * Management determined that there were no changes in the assumptions underlying the value of the derivative instrument between the date of issuance, June 16, 2015, and June 30, 2015. A rollforward of the preferred stock warrant liability and derivative liability categorized with Level 3 inputs is as follows: Preferred Stock Warrants Derivative Instruments Balance—December 31, 2014 $ 1,309 $ — Fair value at issuance date — 1,558 Change in fair value (1,309 ) 2,291 Extinguishment on conversion of convertible notes — (3,838 ) Balance—June 30, 2015 $ — $ 11 Gains and/or losses arising from changes in the estimated fair value of the warrants and embedded compound derivatives were recorded within other income, net, on the condensed consolidated statement of operations.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Net Loss Per Share	13. Net Loss Per Share The Company computes basic and diluted net loss per share using a methodology that gives effect to the impact of outstanding participating securities (the “two-class method”). As the three and six months ended June 30, 2015 and 2014 resulted in net losses attributable to common shareholders, there is no income allocation required under the two-class method or dilution attributed to weighted average shares outstanding in the calculation of diluted net loss per share. The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders: Three Months Ended Six Months Ended June 30, 2015 2014 2015 2014 Numerator: Net loss $ (14,897 ) $ (6,941 ) $ (16,699 ) $ (10,454 ) Accretion of redeemable preferred stock — (13 ) — (26 ) Net loss attributable to common stockholders $ (14,897 ) $ (6,954 ) $ (16,699 ) $ (10,480 ) Denominator: Weighted average common shares outstanding—basic and diluted 5,608,429 3,145,521 4,401,087 3,145,283 Net loss per share attributable to common stockholders—basic and diluted $ (2.66 ) $ (2.21 ) $ (3.79 ) $ (3.33 ) The following potentially dilutive securities outstanding prior to the use of the treasury stock method have been excluded from the computation of diluted weighted-average shares outstanding, as they would be anti-dilutive. As of June 30, 2015 2014 Convertible preferred stock (as converted to common stock) — 5,269,907 Options to purchase common stock 1,983,470 832,184 Warrants to purchase common stock 4,473,440 — Convertible notes and accrued interest (as converted to common stock) — 327,505 Settlement of term loan 85,251 — In addition to the potentially dilutive securities noted above, as of June 30, 2014 the Company had outstanding warrants to purchase redeemable convertible preferred stock, for which the series of stock and number of shares were variable pending the outcome of a future financing event (see Note10). Because the necessary conditions for determining the number of underlying shares had not been satisfied during the six months ended June 30, 2014, the Company has excluded these warrants from the table above. The warrants were cancelled on June 15, 2015, the Effective Time of the Merger.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events The Company has completed an evaluation of all subsequent events through the date of issuance. The Company concluded that no subsequent event has occurred that requires disclosure, except as noted below: On July 10, 2015, the Company posted a letter to shareholders on its website and issued and filed a copy of the letter with the U.S. Securities and Exchange Commission via Form 8-K. The letter stated that RUT58-60 does not fit within the Company’s core focus on differentiated inhaled therapies for pulmonary disease and that the Company is exploring various options to create shareholder value including a possible sale of the asset or strategic partnership whereby further clinical development would be funded by third parties. On August 3, 2015, the Company notified the U.S. Food and Drug Administration that the Phase 1/2 RUT58-60 clinical study was terminated.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2015
Accounting Policies [Abstract]
Goodwill	Goodwill Goodwill represents the difference between the consideration transferred and the fair value of the net assets acquired and liabilities assumed under the acquisition method of accounting for push-down accounting. Goodwill is not amortized but is evaluated for impairment within the Company’s single reporting unit on an annual basis, during the fourth quarter, or more frequently if an event occurs or circumstances change that would more likely than not reduce the fair value of the Company’s reporting unit below its carrying amount. When performing the impairment assessment, the accounting standard for testing goodwill for impairment permits a company to first assess the qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that the goodwill is impaired. If the Company believes, as a result of the qualitative assessment, that it is more likely than not that the fair value of goodwill is impaired, the Company must perform the first step of the goodwill impairment test. The Company has determined that goodwill was not impaired as of June 30, 2015.
In-process Research & Development	In-process Research & Development In-process research & development (“IPR&D”) represents the fair value assigned to research and development assets that were not fully developed at the date of acquisition. IPR&D acquired in a business combination or recognized from the application of push-down When performing the impairment assessment, the Company first assesses qualitative factors to determine whether it is necessary to recalculate the fair value of its acquired IPR&D. If the Company believes, as a result of the qualitative assessment, that it is more likely than not that the fair value of acquired IPR&D is less than its carrying amount, it calculates the asset’s fair value. If the carrying value of the Company’s acquired IPR&D exceeds its fair value, then the intangible asset is written down to its fair value. For the six months ended June 30, 2015, the Company determined that there was no impairment of its IPR&D.

Merger (Tables)

Merger (Tables)	6 Months Ended
	Jun. 30, 2015
Business Combinations [Abstract]
Summary of Acquisition Date Fair Value of Consideration Transferred	The acquisition-date fair value of the consideration transferred is as follows: Number of shares of Company Common Stock owned by Ruthigen stockholders (1) 2,404,835 Multiplied by the price per share of Company Common Stock (2) $ 12.65 Total consideration transferred $ 30,421 (1) The stock transferred in the table above is calculated as the sum of a) 1,921,716 shares of Company Common Stock outstanding at the time of the Merger, b) 379,387 shares of Company Common Stock issued immediately following the closing of the Merger in a private placement, c) 36,000 shares of Company Common Stock issued to certain employees, pursuant to the terms of the Merger Agreement and d) 67,732 shares of Company Common Stock issued pursuant to restricted stock units that became fully vested upon completion of the Merger. (2) The shares outstanding are multiplied by the closing trading price of Company Common Stock as of the Merger date.
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the date of acquisition: June 15, 2015 Cash and cash equivalents $ 9,671 In-process research and development 7,534 Goodwill 15,942 Property and equipment 156 Prepaid and other current assets 140 Total assets acquired 33,443 Accrued expenses and other current liabilities (63 ) Deferred tax liability (2,959 ) Total liabilities assumed (3,022 ) Total net assets acquired $ 30,421
Summary of Supplemental Unaudited Pro forma Information of Financial Results	The following supplemental unaudited pro forma information presents the Company’s financial results as if the acquisition of Ruthigen had occurred on January 1, 2014: Six months ended June 30, 2015 2014 Total revenues, net $ 275 $ 8 Net loss (10,890 ) (16,351 )

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Summary of Carrying Amount	The carrying amounts of the Company’s Notes, including the 5X conversion liability, and the Term Loan as of June 30, 2015 and December 31, 2014 were as follows: At June 30, 2015 At December 31, 2014 Outstanding principal: Notes, including 5X Notes $ — $ 29,088 Term Loan 7,000 — 5X conversion liability — 10,633 Debt discount (294 ) (18 ) Carrying amount $ 6,706 $ 39,703
Summary of Debt Discount Activity	Debt discount activity during the six months ended June 30, 2015 was as follows: Notes, including 2015 Bridge Notes Term Loan Total Balance at December 31, 2014 $ 18 $ — $ — $ 18 Discount on debt issued during the period — 1,547 300 1,847 Amortization of debt discount (18 ) (386 ) (6 ) (410 ) Extinguishment upon conversion of debt — (1,161 ) — (1,161 ) Balance at June 30, 2015 $ — $ — $ 294 $ 294
Schedule of Future Principle Payments	Future principal payments in connection with the Term Loan are as follows: Remainder of 2015 $ — 2016 1,049 2017 2,701 2018 3,250 $ 7,000

Accrued Expenses and Other Cu24

Accrued Expenses and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2015
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following: At June 30, 2015 At December 31, 2014 Accrued vacation $ 81 $ 31 Accrued wages and termination 312 60 Accrued interest payable — 3,338 Accrued clinical & consulting 117 16 Accrued legal & patent 315 44 Accrued other expenses 188 55 Total accrued expenses $ 1,013 $ 3,544

Redeemable Convertible Prefer25

Redeemable Convertible Preferred Stock and Common Stock (Tables)	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Schedule of Redeemable Convertible Preferred Stock and Common Stock	Redeemable Convertible Preferred Stock consisted of the following at December 31, 2014: Shares Common Stock Preferred Stock Issued and Liquidation Carrying Series B 180,980,200 41,788,790 $ 20,894 $ 20,894 2,477,032 Seed 1,219,508 1,219,508 1,331 1,331 72,293 Series A-4 1,307,190 1,307,190 4,000 4,000 474,201 Series B-1 18,687,554 18,687,554 9,344 9,344 1,107,706 Junior Seed 410,000 410,000 820 4 24,307 202,604,452 63,413,042 $ 36,389 $ 35,573 4,155,539

Warrants (Tables)

Warrants (Tables)	6 Months Ended
	Jun. 30, 2015
Rollforward of Preferred Stock Warrants	The following represents a summary of the warrants outstanding at each of the dates identified: Number of Shares Underlying Warrants Warrants Issue Date Classification Exercisable For June 30, 2015 December 31, 2014 Preferred Stock Warrants Various Liability Preferred Stock — 14,544,247 Private Placement Warrants June 15, 2015 Equity Common Stock 3,190,030 — Hercules Warrants June 15, 2015 Equity Common Stock 25,150 — Warrants Assumed in Merger Series A Warrants March - May 2015 Equity Common Stock 1,219,000 — Representative’s Warrants March 2015 Equity Common Stock 37,100 — Underwriter’s Warrant March 2015 Equity Common Stock 2,160 —
Preferred Stock Warrants [Member]
Rollforward of Preferred Stock Warrants	A rollforward of the Preferred Stock Warrants is as follows: Preferred Stock Estimated Fair Balance—December 31, 2014 14,544,247 $ 1,309 Decrease in estimated fair value of warrants — (1,309 ) Cancellation and gain (loss) on extinguishment (14,544,247 ) — Balance—June 30, 2015 — $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2015
Calculation of Fair Value Assumptions Using Black Scholes Option Model	The estimated fair values of employee stock options granted during the six months ended June 30, 2015 and 2014, were determined on the date of grant using the Black-Scholes option-pricing model with the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Expected option life (years) 1.48 - 6.12 5.96 1.48 - 6.22 5.96 Risk-free interest rate 0.68% - 1.91% 1.54% 0.68% - 1.91% 1.54% - 1.57% Expected volatility 65.85% - 73.33% 133% 73.33% - 132.0% 131% - 133% Expected dividend yield 0% 0% 0% 0%
Summary of Stock Option Activity	The following table summarizes stock option activity for the six months ended June 30, 2015: Number of Weighted- Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding—December 31, 2014 732,823 $ 2.08 6.73 $ 5,508 Granted 1,299,251 $ 11.56 Options assumed in Merger 24,400 $ 14.07 Exercised (70,988 ) $ 2.11 Forfeited or expired (2,016 ) $ 2.16 Outstanding—June 30, 2015 1,983,470 $ 8.44 9.07 $ 4,339 Exercisable—June 30, 2015 694,942 $ 3.73 7.71 $ 5,582 Vested or expected to vest—June 30, 2015 1,888,088 $ 8.31 9.03 $ 6,535
Stock-Based Compensation Expense Related to Option Awards	The following table presents the stock-based compensation expense related to option awards for the three and six months ended June 30: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Research and development $ 50 $ 40 $ 81 $ 105 General and administrative 2,661 15 2,664 41 Total stock based compensation expense $ 2,711 $ 55 $ 2,745 $ 146
Summary of Restricted Stock Unit Activity	The following table summarizes stock RSU activity for the six months ended June 30, 2015: Number of Weighted- Fair Value Total Grant Date Outstanding—December 31, 2014 — $ — $ — Granted 329,052 $ 12.65 4,163 Vested (130,435 ) $ 12.65 (1,650 ) Forfeited or expired — — — Outstanding—June 30, 2015 198,617 $ 12.65 $ 2,513
Hercules Warrants [Member]
Calculation of Fair Value Assumptions Using Black Scholes Option Model	The fair value of the warrants was determined using the Black-Scholes option pricing model, using the following assumptions: Exercise price $ 8.35 Fair value of underlying stock $ 11.80 Expected volatility 72.52 % Contractual term 5 years Risk-free interest rate 1.68 % Expected dividend yield 0 %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Schedule of Liabilities Measured at Fair Value on a Recurring Basis	Information about the liabilities measured at fair value on a recurring basis as of June 30, 2015 and December 31, 2014, and the input categories associated with those liabilities is as follows: June 30, 2015 Fair Value Measurements Using Level 1 Level 2 Level 3 Total Liabilities: Embedded compound derivative $ — $ — $ 11 $ 11 December 31, 2014 Fair Value Measurements Using Level 1 Level 2 Level 3 Total Liabilities: Preferred stock warrants $ — $ — $ 1,309 $ 1,309
Summary of Quantitative Information about Fair Value Measurements, Including the Range of Assumptions for the Significant Unobservable Inputs	The following table provides quantitative information about the fair value measurements, including the range of assumptions for the significant unobservable inputs used in the hybrid method valuations of the warrant liability and “with and without” method used for the embedded compound derivative: At December 31, 2014 Time to liquidity event 0.50 years Risk-free interest rate 0.12% Volatility 60% Minority discount 10% Discount for lack of marketability 23%
Schedule of Significant Assumption Used In Model Is Probability	The significant assumption used in the model is the probability of the following scenarios occurring: At Issuance Date At June 30, 2015 Probability of an event of default 10% * Prepayment penalties 1.0% - 3.0% * End of term payment $245,000 * Risk-free interest rate 1.01% *
Schedule of Preferred Stock Warrant Liability and Derivative Liability Categorized with Level 3	A rollforward of the preferred stock warrant liability and derivative liability categorized with Level 3 inputs is as follows: Preferred Stock Warrants Derivative Instruments Balance—December 31, 2014 $ 1,309 $ — Fair value at issuance date — 1,558 Change in fair value (1,309 ) 2,291 Extinguishment on conversion of convertible notes — (3,838 ) Balance—June 30, 2015 $ — $ 11

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders: Three Months Ended Six Months Ended June 30, 2015 2014 2015 2014 Numerator: Net loss $ (14,897 ) $ (6,941 ) $ (16,699 ) $ (10,454 ) Accretion of redeemable preferred stock — (13 ) — (26 ) Net loss attributable to common stockholders $ (14,897 ) $ (6,954 ) $ (16,699 ) $ (10,480 ) Denominator: Weighted average common shares outstanding—basic and diluted 5,608,429 3,145,521 4,401,087 3,145,283 Net loss per share attributable to common stockholders—basic and diluted $ (2.66 ) $ (2.21 ) $ (3.79 ) $ (3.33 )
Schedule of Computation of Diluted Weighted-Average Shares Outstanding Anti-Dilutive	The following potentially dilutive securities outstanding prior to the use of the treasury stock method have been excluded from the computation of diluted weighted-average shares outstanding, as they would be anti-dilutive. As of June 30, 2015 2014 Convertible preferred stock (as converted to common stock) — 5,269,907 Options to purchase common stock 1,983,470 832,184 Warrants to purchase common stock 4,473,440 — Convertible notes and accrued interest (as converted to common stock) — 327,505 Settlement of term loan 85,251 —

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail)	Jun. 15, 2015$ / shares	Jun. 30, 2015$ / shares	Dec. 31, 2014$ / shares
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Reverse stock split of common stock	0.4
Reverse Stock split	1-for-2.5 reverse stock split

Merger - Additional Information

Merger - Additional Information (Detail) - USD ($)	Jun. 15, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Business Acquisition [Line Items]
Number of options, Granted				1,299,251
Deferred tax liability		$ 2,959,000		$ 2,959,000
In-process research and development		7,534,000		$ 7,534,000
Effective tax rate				39.28%
Operating loss		11,319,000	$ 2,451,000	$ 14,065,000	$ 4,862,000
Loss on conversion of convertible notes		(1,170,000)		$ (1,170,000)
Restricted Stock Units [Member]
Business Acquisition [Line Items]
Restricted stock units, options vested				130,435
2015 Bridge Notes [Member]
Business Acquisition [Line Items]
Common stock issued upon conversion of preferred stock and notes	664,559
Loss on conversion of convertible notes	$ (1,170,000)	(1,170,000)		$ (1,170,000)
Pulmatrix Operating [Member]
Business Acquisition [Line Items]
Merger completion date	Jun. 15, 2015
Common stock exchange	0.1481871240
Shares issued upon conversion of convertible preferred stock	70,105,854
Debt instrument conversion, shares of common stock	86,118,402
Pulmatrix Operating [Member] | Oculus Innovative Sciences Inc [Member]
Business Acquisition [Line Items]
Minimum sale price of acquired In-process research and development assets under license agreement	$ 1,000,000
Minimum sale price of acquired In-process research and development assets to be shared with related party	$ 10,000,000
Percentage of sales consideration of acquired In-process research and development assets payable to related party	10.00%
Pulmatrix Operating [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Common stock issued upon conversion of preferred stock and notes	4,155,539
Pulmatrix Operating [Member] | Convertible Notes [Member]
Business Acquisition [Line Items]
Common stock issued upon conversion of preferred stock and notes	5,104,655
Pulmatrix Operating [Member] | 2015 Bridge Notes [Member]
Business Acquisition [Line Items]
Common stock issued upon conversion of preferred stock and notes	664,559
Business acquisition, principal amount of notes assumed	$ 4,500,000
Ruthigen [Member]
Business Acquisition [Line Items]
Merger agreement description	All Pulmatrix Operating stock options granted under the Pulmatrix Operating stock option plans (whether or not then exercisable) that were outstanding at the Effective Time converted into options to purchase Company Common Stock. After the Effective Time, all outstanding and unexercised Pulmatrix Operating stock options assumed by the Company may be exercised solely for shares of Company Common Stock. The number of shares of Company Common Stock subject to each Pulmatrix Operating stock option assumed by the Company was determined by multiplying (a) the number of shares of Pulmatrix Operating common stock that were subject to such Pulmatrix Operating stock option, as in effect immediately prior to the Effective Time, by (b) the Exchange Ratio, as defined in the merger agreement, and rounding the resulting number down to the nearest whole number of shares of Company Common Stock. The per share exercise price for the Company Common Stock issuable upon exercise of each Pulmatrix Operating stock option assumed by the Company was determined by dividing (a) the per share exercise price of Pulmatrix Operating common stock subject to such Pulmatrix Operating stock option, as in effect immediately prior to the Effective Time, by (b) the Exchange Ratio and rounding the resulting exercise price up to the nearest whole cent.
Purchase price allocation description	The purchase price allocation has been prepared on a preliminary basis and is subject to change as additional information becomes available concerning the fair value and tax basis of the assets acquired and the liabilities assumed. Any adjustments to the purchase price allocation will be made as soon as practicable but no later than one year from June 15, 2015, the acquisition date.
Adjustments to purchase price allocation period	No later than one year
Goodwill description				Goodwill is calculated as the difference between the acquisition-date fair value of the consideration transferred and the fair values of the assets acquired and liabilities assumed. The goodwill is not expected to be deductible for income tax purposes. Goodwill is recorded as an indefinite-lived asset and is not amortized but tested for impairment on an annual basis or when indications of impairment exist.
Deferred tax liability	$ 2,959,000
In-process research and development	$ 7,534,000	7,534,000		$ 7,534,000
Operating loss		1,265,000		1,265,000
Transaction costs in connection with merger				6,863,000
Transaction costs in connection with merger		$ 9,956,000		9,956,000
Stock-based compensation expense related to acceleration of vesting				901,000
Expenses related to stay bonuses				995,000
Other expense related to change in fair value of liability classified				2,291,000
Other income related to change in fair value of liability classified				$ 1,309,000	1,275,000
Ruthigen [Member] | IPR&D [Member]
Business Acquisition [Line Items]
Discounted cash flow analysis rate	26.60%
Ruthigen [Member] | Restricted Stock Units [Member]
Business Acquisition [Line Items]
Restricted stock units, options vested	67,732			130,435
Ruthigen [Member] | 2015 Bridge Notes [Member]
Business Acquisition [Line Items]
Loss on conversion of convertible notes				$ 1,170,000
Interest expense				$ 477,000	$ 6,868,000
Ruthigen [Member] | 2013 Employee, Director and Consultant Equity Incentive Plan [Member]
Business Acquisition [Line Items]
Number of options, Granted	24,400

Merger - Summary of Acquisition

Merger - Summary of Acquisition Date Fair Value of Consideration Transferred (Detail) - Jun. 15, 2015 - Ruthigen [Member] - USD ($) $ / shares in Units, $ in Thousands	Total
Business Acquisition [Line Items]
Number of shares of Company Common Stock owned by Ruthigen stockholders	2,404,835
Multiplied by the price per share of Company Common Stock	$ 12.65
Total consideration transferred	$ 30,421

Merger - Summary of Acquisiti33

Merger - Summary of Acquisition Date Fair Value of Consideration Transferred (Parenthetical) (Detail) - shares	Jun. 15, 2015	May. 31, 2014	Jun. 30, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Common stock outstanding			14,646,108	188,625
Ruthigen [Member]
Business Acquisition [Line Items]
Common stock outstanding	1,921,716
Common stock issued		136,000
Employee [Member] | Ruthigen [Member]
Business Acquisition [Line Items]
Common stock issued	36,000
Restricted Stock Units [Member] | Ruthigen [Member]
Business Acquisition [Line Items]
Common stock issued	67,732
Private Placement [Member] | Ruthigen [Member]
Business Acquisition [Line Items]
Common stock issued	379,387	379,387	379,387

Merger - Summary of Estimated F

Merger - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Jun. 15, 2015
Business Acquisition [Line Items]
In-process research and development	$ 7,534
Goodwill	15,942
Deferred tax liability	(2,959)
Ruthigen [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		$ 9,671
In-process research and development	7,534	7,534
Goodwill	$ 15,942	15,942
Property and equipment		156
Prepaid and other current assets		140
Total assets acquired		33,443
Accrued expenses and other current liabilities		(63)
Deferred tax liability		(2,959)
Total liabilities assumed		(3,022)
Total net assets acquired		$ 30,421

Merger - Summary of Supplementa

Merger - Summary of Supplemental Unaudited Proforma Information of Financial Results (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Business Combinations [Abstract]
Total revenues, net	$ 275	$ 8
Net loss	$ (10,890)	$ (16,351)

Goodwill and IPR&D - Additional

Goodwill and IPR&D - Additional Information (Detail) - USD ($)	Jun. 30, 2015	Jun. 15, 2015
Indefinite-lived Intangible Assets [Line Items]
Goodwill	$ 15,942,000
In-process research and development	7,534,000
Ruthigen [Member]
Indefinite-lived Intangible Assets [Line Items]
Goodwill	15,942,000	$ 15,942,000
Goodwill impairment loss	0
In-process research and development	7,534,000	$ 7,534,000
Intangible assets impairment loss	$ 0

Significant Agreements - Additi

Significant Agreements - Additional Information (Detail)	Jun. 16, 2015USD ($)	Jun. 15, 2015Partiesshares	Feb. 08, 2015USD ($)shares	Jun. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2014USD ($)
Other Commitments [Line Items]
Fair value of common stock issued					$ 4,248,000
Revenue recognized during period				$ 170,000	275,000	$ 8,000
Consulting Agreements [Member]
Other Commitments [Line Items]
Shares issued as consideration | shares		100,000
Commission expenses recognized				1,265,000	$ 1,265,000
Number of parties in agreement | Parties		3
Material Transfer Agreement [Member]
Other Commitments [Line Items]
Material transfer agreement term					7 years
Amount recognized during period					0.00%
Material Transfer Agreement [Member] | Maximum [Member]
Other Commitments [Line Items]
Expenses reimbursable					$ 77,000
Tiotropium Bromide Collaboration Agreement [Member]
Other Commitments [Line Items]
Share percentage in gross profit					20.00%
Revenue recognized during period				$ 170,000
Tiotropium Bromide Collaboration Agreement [Member] | Maximum [Member]
Other Commitments [Line Items]
Expenses reimbursable					$ 1,500,000
Palladium [Member]
Other Commitments [Line Items]
Commission paid for loan financing	$ 1,080,000		$ 315,000		1,395,000
Shares issued as consideration | shares			235,844
Commission expenses recognized					4,378,000
Fair value of common stock issued					$ 2,983,000

Debt - Convertible Notes, Inclu

Debt - Convertible Notes, Including 5X Notes - Additional Information (Detail) - USD ($)	Jun. 15, 2015	Jun. 30, 2015	Dec. 31, 2014
Convertible Notes Including 5X Notes [Member]
Debt Instrument [Line Items]
Unsecured convertible notes aggregate principle value			$ 29,088,000
Debt instrument interest rate		6.00%
Debt instrument conversion, shares of common stock	86,118,402
Gain or loss on conversion of notes	$ 0
Common stock shares issued	5,104,655
Convertible Notes Including 5X Notes [Member] | Series B Preferred Stock [Member]
Debt Instrument [Line Items]
Debt instrument conversion price per share		$ 0.50
5X Notes [Member]
Debt Instrument [Line Items]
Unsecured convertible notes aggregate principle value			$ 2,658,000

Debt - Promissory Note - Additi

Debt - Promissory Note - Additional Information (Detail) $ in Thousands	Jan. 21, 2015USD ($)
Debt Disclosure [Abstract]
Bridge loan	$ 350

Debt - 2015 Bridge Notes - Addi

Debt - 2015 Bridge Notes - Additional Information (Detail) - USD ($)	Jun. 15, 2015	Feb. 28, 2015	Jun. 30, 2015	Jun. 30, 2015
Debt Instrument [Line Items]
Amortization of discount				$ 410,000
Loss on conversion of bridge notes			$ 1,170,000	$ 1,170,000
Existing Investor [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued and sold		$ 0
2015 Bridge Notes [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued and sold		$ 4,500,000
Debt instrument interest rate		5.00%
Debt instrument interest rate percentage, maximum		15.00%
Debt instrument interest rate terms				The 2015 Bridge Notes had a stated interest rate of 5% per annum, which would reset to 15% upon an event of default
Debt instrument due date				Feb. 26, 2016
Debt instrument conversion price per share			$ 6.875	$ 6.875
Debt instrument conversion terms				Upon the completion of the Merger, subject to certain limitations, the unpaid principal amount of the 2015 Bridge Notes, plus accrued but unpaid interest through the date of such transaction, automatically converted into shares of common stock of the Company equal to the principal and unpaid accrued interest dollar value divided by $6.875.
Debt instrument, percentage of principal balance payable on event of default				25.00%
Fair value of derivative, recorded as derivative liability			$ 1,547,000	$ 1,547,000
Embedded derivative				The provisions requiring the embedded interest rate reset upon an event of default, automatic conversion of the convertible promissory notes upon the Merger and the put option upon an event of default or failure to close the Merger each represent an embedded derivative instrument requiring bifurcation from the notes. The embedded derivatives were bundled and valued as one compound derivative in accordance with the applicable accounting guidance for derivatives and hedging.
Amortization of discount			276,000	$ 386,000
Common stock issued upon conversion of notes	664,559
Loss on increase in the estimated fair value of derivatives	$ 2,692,000
Loss on conversion of bridge notes	$ 1,170,000		1,170,000	1,170,000
Interest expense			$ 326,000	$ 459,000

Debt - Loan and Security Agreem

Debt - Loan and Security Agreement and Warrant Agreement - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2015USD ($)	Jun. 30, 2014USD ($)	Jun. 30, 2015USD ($)d$ / shares	Jun. 30, 2014USD ($)	Jun. 16, 2015$ / sharesshares	Jun. 11, 2015USD ($)	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Interest expense payable in cash							$ 3,338,000
Hercules Loan and Security Agreement [Member]
Debt Instrument [Line Items]
Fair value of warrant derivative liabilities at issuance, recorded as debt discount			$ 11,000
Interest expense	$ 820,000	$ 156,000	$ 6,784,000	$ 560,000
Hercules Loan and Security Agreement [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Term loan principal amount						$ 7,000,000
Floating annual rate			9.50%
Debt instrument basis spread			8.50%
Basis of debt instrument interest rate			The prime rate as reported by The Wall Street Journal minus 3.25% plus (b) 8.50%.
Debt instrument payment terms			The Company is required to make interest payments in cash on the first business day of each month, beginning on July 1, 2015. Beginning on August 1, 2016, the Company will be required to make monthly payments on the first business day of each month consisting of principal and interest based upon a 30-month amortization schedule
Debt instrument periodic payment frequency			30-month amortization schedule
Repayment charges			$ 245,000
Percentage of prepayment fee	1.00%		1.00%
Percentage of prepayment fee	3.00%		3.00%
Maximum principal amount available for conversion into common shares	$ 1,000,000		$ 1,000,000
Debt instrument, convertible, stock price trigger | $ / shares			$ 11.73
Debt instrument, convertible, threshold trading days | d			7
Number of shares available for purchase of common stock in warrants | shares					25,150
Common stock exercise price | $ / shares					$ 8.35
Warrants expiration date			Jun. 16, 2020
Interest expense	34,000		$ 34,000
Interest expense payable in cash	27,000		27,000
Hercules Loan and Security Agreement [Member] | Term Loan [Member] | Maximum [Member]
Debt Instrument [Line Items]
Repurchase of securities	1,000,000		1,000,000
Hercules Loan and Security Agreement [Member] | Term Loan [Member] | Private Placement [Member] | Minimum [Member]
Debt Instrument [Line Items]
Repurchase of securities	$ 10,000,000		$ 10,000,000
Hercules Loan and Security Agreement [Member] | Term Loan [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Debt instrument basis spread			3.25%

Debt - Summary of Carrying Amou

Debt - Summary of Carrying Amount (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Short And Long Term Debt [Line Items]
Debt discount	$ (294)	$ (18)
Carrying amount	6,706	39,703
Term Loan [Member]
Short And Long Term Debt [Line Items]
Outstanding principal	7,000
Debt discount	$ (294)
Convertible Notes Including 5X Notes [Member]
Short And Long Term Debt [Line Items]
Outstanding principal		29,088
Debt discount		(18)
5X Conversion Liability [Member]
Short And Long Term Debt [Line Items]
Outstanding principal		$ 10,633

Debt - Summary of Debt Discount

Debt - Summary of Debt Discount Activity (Detail) - Jun. 30, 2015 - USD ($) $ in Thousands	Total	Total
Principal Amount Unamortized Debt Discount And Net Carrying Amount Of Liability Component [Line Items]
Beginning balance		$ 18
Discount on debt issued during the period		1,847
Amortization of debt discount		(410)
Extinguishment upon conversion of debt		(1,161)
Ending balance	$ 294	294
Term Loan [Member]
Principal Amount Unamortized Debt Discount And Net Carrying Amount Of Liability Component [Line Items]
Discount on debt issued during the period		300
Amortization of debt discount		(6)
Ending balance	294	294
Convertible Notes Including 5X Notes [Member]
Principal Amount Unamortized Debt Discount And Net Carrying Amount Of Liability Component [Line Items]
Beginning balance		18
Amortization of debt discount		(18)
2015 Bridge Notes [Member]
Principal Amount Unamortized Debt Discount And Net Carrying Amount Of Liability Component [Line Items]
Discount on debt issued during the period		1,547
Amortization of debt discount	$ (276)	(386)
Extinguishment upon conversion of debt		$ (1,161)

Debt - Schedule of Future Princ

Debt - Schedule of Future Principle Payments (Detail) - Term Loan [Member] $ in Thousands	Jun. 30, 2015USD ($)
Debt Instrument [Line Items]
Remainder of 2015	$ 0
2,016	1,049
2,017	2,701
2,018	3,250
Total future principal payments	$ 7,000

Accrued Expenses and Other Cu45

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued vacation	$ 81	$ 31
Accrued wages and termination	312	60
Accrued interest payable		3,338
Accrued clinical & consulting	117	16
Accrued legal & patent	315	44
Accrued other expenses	188	55
Total accrued expenses	$ 1,013	$ 3,544

Redeemable Convertible Prefer46

Redeemable Convertible Preferred Stock and Common Stock - Schedule of Redeemable Convertible Preferred Stock and Common Stock (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Temporary Equity [Line Items]
Preferred stock, shares designated		202,604,452
Preferred stock, shares issued		63,413,042
Preferred stock, shares outstanding		63,413,042
Preferred stock, liquidation value		$ 36,389
Preferred stock, liquidation value		$ 35,573
Common stock issuable on conversion		4,155,539
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	180,980,200
Preferred stock, shares issued	0	41,788,790
Preferred stock, shares outstanding	0	41,788,790
Preferred stock, liquidation value	$ 0	$ 20,894
Preferred stock, liquidation value		$ 20,894
Common stock issuable on conversion		2,477,032
Seed Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	1,219,508
Preferred stock, shares issued	0	1,219,508
Preferred stock, shares outstanding	0	1,219,508
Preferred stock, liquidation value	$ 0	$ 1,331
Preferred stock, liquidation value		$ 1,331
Common stock issuable on conversion		72,293
Series A-4 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	1,307,190
Preferred stock, shares issued	0	1,307,190
Preferred stock, shares outstanding	0	1,307,190
Preferred stock, liquidation value	$ 0	$ 4,000
Preferred stock, liquidation value		$ 4,000
Common stock issuable on conversion		474,201
Series B-1 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	18,687,554
Preferred stock, shares issued	0	18,687,554
Preferred stock, shares outstanding	0	18,687,554
Preferred stock, liquidation value	$ 0	$ 9,344
Preferred stock, liquidation value		$ 9,344
Common stock issuable on conversion		1,107,706
Junior Seed Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	410,000
Preferred stock, shares issued	0	410,000
Preferred stock, shares outstanding	0	410,000
Preferred stock, liquidation value	$ 0	$ 820
Preferred stock, liquidation value		$ 4
Common stock issuable on conversion		24,307

Redeemable Convertible Prefer47

Redeemable Convertible Preferred Stock and Common Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jun. 15, 2015	May. 31, 2014	Jun. 30, 2015	Dec. 31, 2014
Temporary Equity [Line Items]
Preferred stock, shares outstanding				63,413,042
Securities Purchase Agreement [Member]
Temporary Equity [Line Items]
Gross proceeds from issuance of private placement	$ 10,000
Merger Agreement [Member]
Temporary Equity [Line Items]
Exercise price per share of warrants	$ 7.563
Common stock shares converted after merger	1,454,553
Warrants converted after merger	3,190,030
Common Stock [Member]
Temporary Equity [Line Items]
Preferred stock converted to common stock	70,105,854
Common stock issued			2,540,910
Ruthigen [Member]
Temporary Equity [Line Items]
Common stock issued		136,000
Private Placement [Member] | Securities Purchase Agreement [Member]
Temporary Equity [Line Items]
Securities purchase agreement, units sold	24,538,999
Securities purchase agreement, common stock per unit	1
Securities purchase agreement, warrant per unit	2.193140519
Exercise price per share of warrants	$ 0.448266
Private Placement [Member] | Ruthigen [Member]
Temporary Equity [Line Items]
Gross proceeds from issuance of private placement			$ 2,600
Common stock issued	379,387	379,387	379,387
Common stock, price per share		$ 6.875	$ 6.875
Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares outstanding	63,413,042

Warrants - Preferred Stock Warr

Warrants - Preferred Stock Warrants Issued With Notes Payable to Stockholders - Additional Information (Detail) - Preferred Stock Warrants [Member] $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015USD ($)$ / sharesshares	Jun. 30, 2014USD ($)	Jun. 30, 2015USD ($)$ / sharesshares	Jun. 30, 2014USD ($)	Dec. 31, 2014shares
Class of Warrant or Right [Line Items]
Number of shares available for purchase of common stock in warrants | shares	0		0		14,544,247
Other income from change in fair value of warrant liability | $	$ 152	$ 727	$ 1,032	$ 1,309
Pulmatrix Operating [Member]
Class of Warrant or Right [Line Items]
Factor used for determining warrant exercisable	0.25		0.25
Warrants term			10 years
Number of shares available for purchase of common stock in warrants | shares	0		0
Pulmatrix Operating [Member] | Series B Preferred Stock [Member]
Class of Warrant or Right [Line Items]
Factor used for determining warrant exercisable	0.25		0.25
Conversion price for warrants			$ 0.50
Exercise price per share of warrants	$ 0.50		$ 0.50

Warrants - Rollforward of Prefe

Warrants - Rollforward of Preferred Stock Warrants (Detail) - 6 months ended Jun. 30, 2015 - Preferred Stock Warrants [Member] - USD ($) $ in Thousands	Total
Class of Warrant or Right [Line Items]
Preferred Stock Warrants, beginning balance	14,544,247
Decrease in estimated fair value of warrants	0
Cancellation and gain (loss) on extinguishment	(14,544,247)
Preferred Stock Warrants, ending balance	0
Beginning balance	$ 1,309
Decrease in estimated fair value of warrants	(1,309)
Cancellation and gain (loss) on extinguishment	$ 0

Warrants - Common Stock Warrant

Warrants - Common Stock Warrants Issued in Pulmatrix Operating Private Placement - Additional Information (Detail) - Jun. 30, 2015 - USD ($)	Total
Pulmatrix Operating [Member]
Class of Warrant or Right [Line Items]
Share price	$ 10
Average daily trading volume	40,000
Pulmatrix Operating [Member] | Maximum [Member]
Class of Warrant or Right [Line Items]
Proceed from strategic license agreement	$ 20,000,000
Gross proceeds from issuance of securities	$ 20,000,000
Pulmatrix Operating [Member] | Sixty Consecutive Trading Days [Member]
Class of Warrant or Right [Line Items]
Share price	$ 12.50
Pulmatrix Operating [Member] | Minimum [Member]
Class of Warrant or Right [Line Items]
Percentage of weighted average price of common stock	150.00%
Pulmatrix Operating [Member] | Thirty Consecutive Trading Days [Member]
Class of Warrant or Right [Line Items]
Average daily trading volume	80,000
Consideration for unexercised portion of the warrant per share of common stock	$ 0.001
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants Outstanding	3,190,030
Exercise price per share of warrants	$ 7.563

Warrants - Warrants Assumed in

Warrants - Warrants Assumed in Merger - Additional Information (Detail) - $ / shares	Jun. 15, 2015	May. 31, 2014	Jun. 30, 2015
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Number of warrants issued			1,219,000
Ruthigen [Member]
Class of Warrant or Right [Line Items]
Common stock issued		136,000
Ruthigen [Member] | Warrant [Member]
Class of Warrant or Right [Line Items]
Warrant exercise price			$ 22.65625
Number of shares issued under over allotment option			37,100
Ruthigen [Member] | Private Placement [Member]
Class of Warrant or Right [Line Items]
Common stock issued	379,387	379,387	379,387
Common stock, price per share		$ 6.875	$ 6.875
Ruthigen [Member] | Over-Allotment Option [Member]
Class of Warrant or Right [Line Items]
Warrant exercise price			$ 22.65625
Number of shares issued under over allotment option			2,160
Ruthigen [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrant exercise price		$ 17.83
Ruthigen [Member] | Series A Warrants [Member] | IPO [Member]
Class of Warrant or Right [Line Items]
Number of warrants issued		1,219,000
Warrant exercise price		$ 18.125
Warrant per share		0.4
Consideration for warrants		$ 0.00025
Ruthigen [Member] | Series A Warrants [Member] | IPO [Member] | Period of 20 Consecutive Business Days [Member]
Class of Warrant or Right [Line Items]
Warrant exercise price		18.125
Ruthigen [Member] | Series B Warrant [Member]
Class of Warrant or Right [Line Items]
Warrant exercise price		22.28
Ruthigen [Member] | Series B Warrant [Member] | IPO [Member]
Class of Warrant or Right [Line Items]
Warrant exercise price		$ 22.65625
Warrant per share		0.4

Warrants - Calculation of Fair

Warrants - Calculation of Fair Value Assumptions Using Black Scholes Option Model (Detail) - Jun. 30, 2015 - Hercules Warrants [Member] - $ / shares	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price	$ 8.35
Fair value of underlying stock	$ 11.80
Expected volatility	72.52%
Contractual term	5 years
Risk-free interest rate	1.68%
Expected dividend yield	0.00%

Warrants - Common Stock Warra53

Warrants - Common Stock Warrants Issued With Term Loan - Additional Information (Detail) - Hercules Warrants [Member] - USD ($) $ / shares in Units, $ in Thousands	Jun. 30, 2015	Jun. 16, 2015	Jun. 11, 2015
Class of Warrant or Right [Line Items]
Term loan in the principal amount			$ 7,000
Number of warrants granted	25,150	25,150
Warrant exercise price		$ 8.35
Value of warrants	$ 198

Warrants - Summary of the Warra

Warrants - Summary of the Warrants Outstanding (Detail) - shares	6 Months Ended
	Jun. 30, 2015	Jun. 16, 2015	Dec. 31, 2014
Preferred Stock Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date, description	Various
Warrants, Classification	Liability
Warrants, Exercisable For	Preferred Stock
Warrants Outstanding	0		14,544,247
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Jun. 15, 2015
Warrants, Classification	Equity
Warrants, Exercisable For	Common Stock
Warrants Outstanding	3,190,030
Hercules Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Jun. 15, 2015
Warrants, Classification	Equity
Warrants, Exercisable For	Common Stock
Warrants Outstanding	25,150	25,150
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Classification	Equity
Warrants, Exercisable For	Common Stock
Warrants Outstanding	1,219,000
Series A Warrants [Member] | Minimum [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	May 31, 2015
Series A Warrants [Member] | Maximum [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	May 31, 2015
Representative's Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	May 31, 2015
Warrants, Classification	Equity
Warrants, Exercisable For	Common Stock
Warrants Outstanding	37,100
Underwriter's Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	May 31, 2015
Warrants, Classification	Equity
Warrants, Exercisable For	Common Stock
Warrants Outstanding	2,160

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jun. 15, 2015	Jun. 30, 2015	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash received from exercise of stock options			$ 150
Intrinsic value of options exercised			531
Unrecognized stock-based compensation expenses		$ 8,132	$ 8,132
Unrecognized stock-based compensation expense, period for recognition			9 years 11 months 12 days
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units, granted			329,052
Restricted stock units, options vested			130,435
Ruthigen [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units, granted			329,052
Restricted stock units, options vested	67,732		130,435
Stock-based compensation		$ 1,755	$ 1,755
2013 Employee, Director and Consultant Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			0
Shares available for future grant		1,191,598	1,191,598
Aggregate shares of Common Stock that may be delivered under options outstanding		35,556	35,556
Weighted-average grant-date fair value of stock option granted			$ 11.56
2013 Employee, Director and Consultant Equity Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			2,713,261
Employee, Director, and Consultant Stock Plan (the "2003 Plan") [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			0
Aggregate shares of Common Stock that may be delivered under options outstanding		629,983	629,983

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of options, Outstanding beginning balance	732,823
Number of options, Granted	1,299,251
Number of options, Options assumed in Merger	24,400
Number of options, Exercised	(70,988)
Number of options, Forfeited or expired	(2,016)
Number of options, Outstanding ending balance	1,983,470	732,823
Number of options, Exercisable	694,942
Number of options, Vested and expected to vest	1,888,088
Weighted average exercise price, Outstanding beginning balance	$ 2.08
Weighted average exercise price, Granted	11.56
Weighted average exercise price, Options assumed in Merger	14.07
Weighted average exercise price, Exercised	2.11
Weighted average exercise price, Forfeited or expired	2.16
Weighted average exercise price, Outstanding ending balance	8.44	$ 2.08
Weighted average exercise price, Exercisable	3.73
Weighted average exercise price, Vested and expected to vest	$ 8.31
Weighted average remaining contractual term, Outstanding beginning balance	9 years 26 days	6 years 8 months 23 days
Weighted average remaining contractual term, Exercisable	7 years 8 months 16 days
Weighted average remaining contractual term, Vested or expected to vest	9 years 11 days
Aggregate intrinsic value, Outstanding beginning balance	$ 5,508
Aggregate intrinsic value, Outstanding ending balance	4,339	$ 5,508
Aggregate intrinsic value, Exercisable	5,582
Aggregate intrinsic value, Vested or expected to vest	$ 6,535

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense Related to Option Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 2,711	$ 55	$ 2,745	$ 146
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	50	40	81	105
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 2,661	$ 15	$ 2,664	$ 41

Stock-Based Compensation - Esti

Stock-Based Compensation - Estimated Fair Values of Employee Stock Options Granted (Detail) - Employee Stock Option [Member]	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option life (years)		5 years 11 months 16 days		5 years 11 months 16 days
Risk-free interest rate		1.54%
Expected volatility		133.00%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option life (years)	1 year 5 months 23 days		1 year 5 months 23 days
Risk-free interest rate	0.68%		0.68%	1.54%
Expected volatility	65.85%		73.33%	131.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option life (years)	6 years 1 month 13 days		6 years 2 months 19 days
Risk-free interest rate	1.91%		1.91%	1.57%
Expected volatility	73.33%		132.00%	133.00%

Stock-Based Compensation - Su59

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Detail) - Jun. 30, 2015 - Restricted Stock Units [Member] - USD ($) $ / shares in Units, $ in Thousands	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, Granted	329,052
Number of units, Vested	(130,435)
Number of units, Forfeited or expired	0
Number of Units, Ending Balance	198,617
Weighted average grant date fair value, Granted	$ 12.65
Weighted average grant date fair value, Vested	12.65
Weighted average grant date fair value, outstanding	$ 12.65
Total grant date fair value, Granted	$ 4,163
Total grant date fair value, Vested	(1,650)
Total grant date fair value, Outstanding, Ending balance	$ 2,513

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Liabilities Measured at Fair Value on a Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Embedded Compound Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Derivative liability	$ 11
Preferred Stock Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Derivative liability		$ 1,309
Level 3 [Member] | Embedded Compound Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Derivative liability	$ 11
Level 3 [Member] | Preferred Stock Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Derivative liability		$ 1,309

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 15, 2015	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Fair Value Assets Liabilities Quantitative Information [Line Items]
Loss on increase in estimated fair value of derivatives	$ (2,692)	$ (2,692)	$ (2,291)
Loss upon the conversion Bridge Notes including the extinguishment of the embedded compound derivative		(1,170)	(1,170)
Fair Value, Measurements, Recurring [Member] | Embedded Compound Derivative [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Derivative liability		11	11
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Embedded Compound Derivative [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Derivative liability		11	11
2015 Bridge Notes [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Fair value of derivative liability		1,547	1,547
Loss upon the conversion Bridge Notes including the extinguishment of the embedded compound derivative	$ (1,170)	$ (1,170)	$ (1,170)
Debt instrument conversion percentage		100.00%	100.00%
Preferred Stock Warrants [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Warrant outstanding		0	0	14,544,247
Preferred Stock Warrants [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Derivative liability				$ 1,309
Preferred Stock Warrants [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Derivative liability				$ 1,309

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Quantitative Information about Fair Value Measurements, Including the Range of Assumptions for the Significant Unobservable Inputs (Detail) - 12 months ended Dec. 31, 2014 - Fair Value, Measurements, Recurring [Member] - Level 3 [Member] - Preferred Stock Warrants [Member]	Total
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Time to liquidity event	6 months
Risk-free interest rate	0.12%
Volatility	60.00%
Minority discount	10.00%
Discount for lack of marketability	23.00%

Fair Value Measurements - Sch63

Fair Value Measurements - Schedule of Significant Assumption Used in Model is Probability (Detail) - Jun. 30, 2015 - Fair Value, Measurements, Recurring [Member] - Level 3 [Member] - Embedded Compound Derivative [Member] - USD ($) $ in Thousands	Total
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Probability of an event of default	10.00%
End of term payment	$ 245,000
Risk-free interest rate	1.01%
Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment penalties	1.00%
Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment penalties	3.00%

Fair Value Measurements - Sch64

Fair Value Measurements - Schedule of Preferred Stock Warrant Liability and Derivative Liability Categorized with Level 3 (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2015USD ($)
Preferred Stock Warrants [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 1,309
Change in fair value	(1,309)
Extinguishment on conversion of convertible notes	0
Derivative Instruments [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value at issuance date	1,558
Change in fair value	2,291
Extinguishment on conversion of convertible notes	(3,838)
Ending balance	$ 11

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net loss	$ (14,897)	$ (6,941)	$ (16,699)	$ (10,454)
Accretion of redeemable preferred stock		(13)		(26)
Net loss attributable to common stockholders	$ (14,897)	$ (6,954)	$ (16,699)	$ (10,480)
Denominator:
Weighted average common shares outstanding-basic and diluted	5,608,429	3,145,521	4,401,087	3,145,283
Net loss per share attributable to common stockholders-basic and diluted	$ (2.66)	$ (2.21)	$ (3.79)	$ (3.33)

Net Loss Per Share - Schedule66

Net Loss Per Share - Schedule of Computation of Diluted Weighted-Average Shares Outstanding Anti-Dilutive (Detail) - shares	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Term Loan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	85,251
Warrants To Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	4,473,440
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	1,983,470	832,184
Convertible Notes and Accrued Interest [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share		327,505
Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share		5,269,907